Scotts s1642 Hydro Transmission

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Scotts s1642 Hydro Transmission

Scotts I have a Scotts s1642 with a hydrostatic transmission. I was cutting the grass and the mower start jerking a little. I put it in neutral turned the mower off and got off to see whatever I was looking for. When I started the mower back up it would not go forward or backward when taken out of neurtral. Any ideas? Any help would be appreciated.
Lee I have the same exact lawn mower and problem that you are experiencing!

Today I went to cut the grass and did just as you had done. Got back on it to get it going and it wouldn't move :(

I am really hoping that I do not have to get this transmission rebuilt. What a joy that will be...

Garry I bought my S1642 2001-09. Had to put a new trans in in 2004-03 and it is out again now (2006-05). When it was repaired in 2004 JD dealer said these Scotts mowers were made the absolute cheapest of all JD products. No way to repair the Hydro trans, all sealed up. Just replace at about $650 2 years ago. No telling what it costs now.
Scotts Oooof!!! That's a shot to the wallet. I could find a used riding mower in good condition for that price. Did JD offer a rebuild if possible? Or is it all or nothing? I suppose the new trany's warranty just expired on you as well. Thanks for your response(s).
Lee To the original poster: I FIXED THE PROBLEM!!!

Considering that you and I had the same EXACT problem under almost the same EXACT circumstances, this will probably be of great importance to you...

After reading Gary's response and then contacting the nearest JD dealership (which would charge a MINIMUM of $75 just to look at the thing) I decided to take matters into my own hands and rip out the transmission for disassembly. The worst thing that could have happened, after all, was that they would have told me I needed a new transmission anyway, right?

So anyways, on to the good stuff...

7 nuts/bolts and 1 cotter pin later, the entire rear housing was out of the mower and ready to be torn down in my garage.

After turning the housing upside down and supporting it so it would sit even, I carefully started removing the 20 bolts holding the bottom cover of the housing together. Once the cover was off I IMMEDIATLY found the source that was causing my (and more than likely your) problem.

If you look at pg. 10 of this .pdf file I found online:

you will see an entire parts list for our exact transmission. Notice part #45 (which is a pin). This pin, over time, worked it's way out of the lever housing (part #42) which made the mower not want to go anywhere while trying to use the forward and reverse lever next to the seat.

I carefully tapped this lever back into place and to insure that this wouldn't happen again, took a piece thick aluminum twine and tied it through and around the rod (since it's hollow) to eliminate any considerable amount of side-to-side movement.

That's it! That little stinkin pin caused the entire tractor to remain useless for over a week for me, until today!

After fixing that, the cover was then ready to be put back on. I went and bought some Permatex Ultra Black Silicon Gasket Maker from the auto parts store:

and sealed the bottom cover of the housing onto the transmission.

After letting the transmission sit for a few hours so that the gasket maker could set up properly, I then filled the transmission up with ~2.5 qts of regular 10w-30 motor oil as instructed by Tuff Torq, the producer of our transmission, here in the "Troubleshooting" section of their site:

Wouldn't you know it. The mower worked GOOD AS NEW! My dad and I were so excited that we got it going! I was also able to let it sit over night and no leaks or anything! I also cut grass today for about 2 hours, or so, and it ran great!

Now, not everyone is THAT mechanically inclined, but I feel that if you are used to changing your own oil and spark plugs in the family car, etc. than this job really shouldn't be that terribly difficult. It took me an entire day to finish this project from start to finish since I have never really worked on a lawn mower before, but after completing it, I am confident that I can finish the job if I had to do it again in under 5 hours or so...

If you have any more questions, email me at:

and I'll try to remember to check that email so that I can help you out.

Good luck and PLEASE at the very least highly consider doing this yourself before shelling out the cash for a new transmission!

Cya! :)

Garry Lee are you sure ALL of the S1642's have that same transmission???
Where can I get a repair manual for this mower?

Lee I have no idea where to find the manual, but I don't see why all S1642's wouldn't have the same transmission.

There's an easy way to check though:

While looking at the back of the housing, you should see a white model number sticker right on the housing itself. It will say something like:

Tuff Torq

This means that K51 is the model number of the transmission. Check yours too. I'm almost positive it will be the same thing....

Charles Guys... I had the same problem last week. After I removed the deck I found the drive belt had broken, a simple fix if you can figure out how to route the new one, any ideas? Of course, this might be coincidental to the transmission "pin" problem but I will have to get the belt back on first to see. If the belt isn't it, I plan to tear into the transmission.
Lee Yeah, the belt would be a much easier fix, TRUST ME!

But if it isn't, feel free to ask me any questions since I'm pretty familiar with what's involved.

I'll also try and find some time this weekend to sneak under my mower and get that belt route for you too :)

Charles That would be great, Lee... I have had zero luck finding the drive belt routing on the web. Thanks.
Charles Gents...
Here is a link to a manual showing drawings for this model mower. It has the routing for the drive belt, which is not in the owners manual. What was JD thinking?

(Thanks Lee, no need to crawl under your mower now)

Lee Sweet!

Thanks for posting that up!

No more "trial and error" now :D

Scotts Thanks a lot for looking into this. I am not the most mechanically inclined individual in the world, but my father-in-law is. He would likely have looked into this if it were his mower. I'm sure he will understand all this stuff and be able to help me.

NOTE: I did notice one thing. The forward/reverse lever became really loose when the mower quit going forward and backward. I wonder if this is the pin, the belt, or both?

Lee YES!

I too noticed the forward/reverse lever becoming really loose when mine stopped working. Almost like there was no more resistance (which is exactly what happened).

For that reason, I KNEW it was a problem inside the transmission and not just a simple belt replacement.

Looks like you'll be digging into that tranny sooner than you think...unless you want to pay through the nose for a new one, that is :(

Lee I also forgot to mention that the reason why the lever feels "loose" now is because it is no longer connected to the rest of the assembly within the transmission. This is because, obviously, the pin no longer allows the two to connect together and the lever no longer engages/moves with the rest of the parts (gears, etc.) within the housing...
Denny Allen Lee,
You are a saint. Mine went out a yr. ago. After pricing 1 @ J.D. I decided to tear it down and I need a few minor parts and couldn't find them anywhere. My white sticker is not readable and no one new who made the trans. With your info mine is a Tuff Torq K51 and now I can order the parts. I already bought a new mower but at least I can fix my S-1642 now. SHAME all over J.D. they qyoted me $800.00 and I install it and no internal parts available. Ha! Ha! Thanks so much Lee.
Denny from GA

Louis After reading Lee's post, I got enough nerve to take the trans out to get a closer look. I opened it up and found everything as it should be. I then bolted everything together again but I was only able to get 1.5 qts. in the tranny. Before I took it apart the mower would move very slow, now it wouldn,t move at all. So I took it out and tore it down again to find everything in place. This time after putting it back together I removed the filter and spring. This time it took all 2.5 qts of 10w 30. I do remember before tearing it down the bottom of the tranny was wet with oil. I think my problem mayhave been low oil. Mower works great now, I can even pop a wheelie like it was new. Thank for all the info you guys are great.
Louis anyone know where i can get a 42 in mower deck for my scotts s1642 riding mower. i checked on a new one, they are pretty expensive. thought maybe someone had a used one out there in pretty good shape.
Ray I have just experienced the same problem with my 1642, not that I have your information, I'm going to try and fix it this weekend. Thanks for all your comments.
Peter Lee, I too have a 1642 and also had the loss of mobility as you described. I immediately thought of the drive belt as it broke on me a couple years ago. When I went to the JD dealer to get a new belt this time, I questioned the parts counter About what could cause the “no go” situation. I was told to examine the pulley on top of the transmission, as the splined material is softer than that of the splined shaft from the transmission.
Well wouldn’t you know it, the JD guy was on the money, that’s exactly what was wrong. The really interesting thing is that the new splined coupling for the pulley only cost $10.00.
I also asked if these Scots were known for this problem and was told no, not any more than any other JD. While I was at the JD place, I looked at some high end mowers and all the transmissions are of the same design as the Scotts.

Peter Lee, I too have a 1642 and also had the loss of mobility as you described. I immediately thought of the drive belt as it broke on me a couple years ago. When I went to the JD dealer to get a new belt this time, I questioned the parts counter About what could cause the “no go” situation. I was told to examine the pulley on top of the transmission, as the splined material is softer than that of the splined shaft from the transmission.
Well wouldn’t you know it, the JD guy was on the money, that’s exactly what was wrong. The really interesting thing is that the new splined coupling for the pulley only cost $10.00.
I also asked if these Scots were known for this problem and was told no, not any more than any other JD. While I was at the JD place, I looked at some high end mowers and all the transmissions are of the same design as the Scotts.

Bill HELP!! I have the 2048 Scott's and it will try to move forward or reverse but very little. No smell of burned oil overall in great condition just won't move. It has the TuffTorq K62 SBR on tag. Any thoughts on problem I think I can repair, X CanAm pit crew gear head.
Philip DiGiovanni I located the drive belt for the tractor from the dealer, but could not get a schematic anywhere....any further help?
digidds I have the routing schematic for the drive belt.....respond to this message
Kenn Harp I need to replace my drive belt......can you send the schematic?
Jackie what is the belt # you have for that. My s1642 broke its drive belt my manual said it was a gx10065. Dealer said it doesnt exist anymore. I found some s1642 use a gx10851, I found out one is 96"long and one is 95.9 " long. The dealer had a gx10851, and it was about 3-4 inches short,any help would be appreciated, thanks
Charlie Okay here's a simple question: Does the ground drive belt or lack thereof affect motion?
Alan Horn I had the same thing happen(mower would not go
forward or reverse). All it was was a shaft key
that goes in a groove in the rear axle. I had a
flat tire and had taken the tire off. Evidently,
the key which is square and approximately 2 to
2 1/2 inches long stayed in the tire rim and was
lost when I took the tire to be repaired. The key
only cost 46 cents.

w moltz How do you drain oil, add oil, and check the oil level on the 1642 transaxel? I don't see any obvious drain or add plugs. Are they on top and, if so what's the easiest way to get to them?
James B Smith Tell me where i can find parts for transmission.
The input shaft, hub,and seals..
and filter

part 1720424 shaft
part 179902 hub

Need this info. asap if possible.
Thank You

Rob D Anyne know visually how much oil shold be in one of these trans?

If I take off the sealing cap and look in where the spring and filter disc are, should the level be above the top of the filter disc or below.

Thank you for any assistance you might be able to give me.

Klute Hey, I just replaced the drive belt and was having a problem figuring out where the big spring that keeps tension on the drive belt is attached.

I know that one end hooks into the notch by the pulley, but the other end confounds me at to where it hooks to.

The spring fell off and was laying on top of mower deck as the drive belt was broken.

It is labeled #9 on the JD schematic. (belt, traction drive)


Chukster O.k. I found out that it is the drive belt that broke on my s1642, I have downloaded the schematic diagram to use in replacing it, I am sending my wife at lunch to pick up the belt, the question I have is how hard is it to get to the pulleys? Am I going to have to take the deck off? Any detailed help with this will be greatly appreciated.
BOZ I have an 18.5 HP Scotts from Home Depot. I got it back in the late 90's. I looked over the trany from top to bottom, and can't find any transmission fluid filler hole. I thought that these were sealed units. My tractor goes at a snails pace. Very little fwd., or reverse. Please, someone help. Transmissions aren't cheap. I'll take it apart if i have to. Please respond soon, Grass is getting deeper...
Klute BOZ...

I think it is sealed trany.

Did you check your motion drive belt? Maybe it is very lose and therefore not engaging the tranny. Or maybe the tension spring is lose or fell off.

ken I have a Scotts 20HP, 46" cut made by John Deere purchased in 2001. It began making a noise in reverse a couple of months ago and that progressed to the forward gears and one day it just stopped moving. It has a Tuff-Torq K-51 hydrostatic transmission. I called Tuff-Torq service and they said they sell parts for the unit. Tore down the unit and found nothing wrong.
The belt had some cracks but I don't believe this was keeping it from moving. Replaced belt and refilled transmission with AMS/OIL 20W/50. It now runs like a top. If you have similar problems, be sure and check that debris has not built up on top of the transmission which prevents the engage/disengage rod from being pushed in all the way. I think this was the problem with mine. The tranny is serviceable regardless of what John Deere might say. You can find Tuff-Torq service on the web.

Old_Henry Someone please tell me right away - how much oil should there be in a K51 TuffTorq box? Is there some reference that I can use as a 'level' marker? I have the axle out, and the level is below the filter.
Kim My mower is 10 years old. When you try to engage the mower won't go forward or backward. Well it will move very slowly if you barely (I mean very barely) move to engage. If you try to engage it makes a really loud noise. Kinda like sticking something in a fan. My husband replaced the belt. He thinks the fan is loose. Any help would be appreciated.

Brian Does anyone know what transmission belt # is correct for the Scott 1642H. JD dealer gave me # GX10851 which is 3 or 4 inches to short.
Mark Belt # GX10851 is not 3-4 inches too short as one has said. Just replaced mine on the S1642 tractor and is works fine.

Jim Curtis I have a Tuff Torq K51. I have plenty of power forward and very little in reverse. Any suggestions? Also how do you remove the sealing cap(part#1718055)?
I would like to check the oil level.

Jim Curtis I have a Tuff Torq K51. I have plenty of power forward and very little in reverse. Any suggestions? Also how do you remove the sealing cap(part#1718055)?
I would like to check the oil level.

earl Great info!. My Scott S1642 hydro trani encountered nogo issue yesterday. Makes a loud whining sound and just barely moves forward. Nogo in reverse. Appreciate the details and reference material that Lee. Comments by others will help me. Issue occured right after I changed engine oil/fliter and thought I got oil on drive belt, but guess nogo was just a coincident. - thanks

Re: Scotts s1642 Hydro Transmission

Took tranaxle apart and found that the spline on both the pump shaft (part #1720424which must be purchased as shaft kit 19216899475 which includes bearing, clips and dust cover from Tuff Torq Corporation Phone 423-585-1977, and Derrick Dalton was very helpful) In my case the pulley (only from John Deere) inside spline was also damaged so that is now new. Follwoing is withunit on bench. In reassembling, must be carefull with part alignment and keeping a very small pin in it's place while making things fit together. Once tranaxle was reassembled, then took the old large oil filler cap off, by a little prying, a bit of 3 in 1 oil, a bit of prying and so on. Then to add oil I removed the filter screen, added oil until I could easily see it then took a piece of auto heater hose (about 3" long)tightly fit the pump shaft placing about 1.5" on pump shaft, then hose clamped 1/2 drill bit into other end of hose. Drill bit fit my variable speed drill and ran drill to get the air out while moving shifter between forward and reverse and at times placing unit in tow (out of gear). I'm still not satisified with axle speed, seems too slow, so working on that. Per Tuff oil level should be maintained 24~38 mm (15/16" to about 1 1/2") below lip large black cap port.

Mark Harper There is a common problem with these transaxles where the springs inside the drive pump punch through the cylinder block and pieces become sheared off. The pieces then go through the pump and score the aluminum face of the inner case. The symptom is a rather normal running transmission that starts to jerk and eventually loose forward, reverse or both. The drive lever will often jump in your hands as yo try to keep it in the forward position. Tuff Torq makes a repair kit that contains the pump, inside case an seals. Luckily, the motor is usually not affected. Check for scoring of the mating faces of the inner case (connecting the pump and motor), the length of the piston springs in the pump and for pieces of metal in the case.
lee white i have a 2001 john deere sabr 1742hs i belive it has a tuff torq k51 transaxel,it would not go up hill in forward it works fine in reverse, i had the drive belt replaced to no avail, the john deere dealership said it is internal and they want $600.00 just for the transaxel, do you have any ideas.
thanking you in advance

tracy ramin need drive belt diagrahm
Dave I am having the same problem with the replacement belt for the Scotts 1642 mower I got from the dealer. It seems 3 or 4 inches short.
Dave I installed the GX10851 drive belt for my s1642 and it works great. The drive belt diagram is a must. Thanks!
Brian I replaced mt traction belt but having a heck of a time trying to reattach the idler pully tension spring anyone have a tip?


Allan Does anyone know where I can buy a rear bagger for my scotts s1642
Ken Marien I got the original belt from Eastern Bearings in Fitchburg MA today for $13. To put it on I pulled the spring loaded ideler pully back with two screw drivers while rolling the belt on by turning the engine pully by hand. It popped right on. I had to remove the steering linkage and the brake engagement link but it was easy. (with Mower deck removed.)

I had the K51 transmission all apart and back together with no apparent damage, cleaned the filters with brake clean and refilled with 2 1/2 qts of 20-50 motor oil and it still slips on a hill. Any ideas? Do these just wear out and slip when they get 10 years old?

derek "a lost of power along with a high pitched scream when tranny is engaged" ---- this is my exact same problem, is there a resolution to this? it seems to be okay in reverse, except when i cut the wheel to the left, then loss of power to the wheels and high pitched screaming.
malaang hello
does anybody know what size belt do i need for my Scott made by JD and the label says
Model #1642h.
Ground Drive Belt GX10065
Mower Drive Belt M124895

Again, it is Scott 16HP/42 Automatic.

I have tried 42" belt, but it was short. Not sure whether I install it correctly or not. some can give me the schematic for the belt install, i really appreciate it.


Glenn My S1642 began to slip in forward and reverse so I replaced the ground drive belt and mower belt with no improvement in the results. Mine exhibits different symptoms than described here. When going up hill, the transmission makes a noise like it is underheavy load (not sqeaking or grinding but like hydraulics under load) and it begins to slip. Is this a lack of fluid? Do you have to pull the trans to refill it? Seems like this is a widespread problem...
cecil Where do you buy replacement belt gx10065? I can not find anyone that sells that belt

Glenn They no longer make the GX10065. The replacement is a JD GX10851. I replaced the original wth this one and it fit perfectly.
Glenn Update... I was cutting the lawn last night and just finishing the last row when the trans completely quit. I felt it let go, heard some grinding and that was it. So I guess it's not the fluid level ;)
Glenn It looks like there are 4 distinct issues that people have reported here regarding the transaxle:

1) Broken Ground Drive belt
2) Stripped splines on the trans pulley
3) Pin popping out inside the trans for the shifter
4) Low fluid level

Well, my trans appears to have just plain wore out. It started slipping and groaning a bit last year and then let go with grinding and then nothing this year.

I replaced the K51A with a new unit from TuffTorq for $595 after seeing that the pump repair kit alone is over $300. It works like new (except for very tight shifter movement?) They don't want the old unit back so I am going to rip it down when I'm bored to see what happened. I believe that I lost a gear(s) in the trans based on the slipping and grinding followed by a complete failure of the unit.

I got 8 years out of it so I'm not too p'd off. I just hope this one lasts as long!

ecojim1 Peerless trans moves 10 ft and stops. I located a plastic filler plug on top and trans appears to be full (but dirty oil). The bottom of the trans case has been dripping a little oil for awhile. That oil is clear and clean. Is it possible that the trans is just low on oil? The trans doesn't appear to have a drain plug, and I don't know if it has a filter that can be replaced. Belts and tension are new and okay. Any suggestions?
gerard o connell what belts go on this machine
bradley how do i change the drive belt not the mower belt the one that goes to the trans
heath i have fixed 10 or 20 of these for peolpe.if it want pull and the belt is good and still on.the pulley that is on top of the transmission is bad to strip out it very common.
Jesse My 1642 was purchased in 2000 at Home Depot.It has been dependable until yesterday.I put a new battery on it in April 09. I mowed with it Wednesday.Saturday it would not start.I found out my battery is dead again.I put a new battery on it and it starts and runs great as long as you keep the brake pedal down.If I release the brake it dies.If I engage the blade with it running with the brake pedal down that also kills it.So now I'm trying to find a wiring diagram.I think my problem is a safety switch but I don't know which one it is.It has one under the seat,one on the brake,one on the PTO and a reverse button to use while mowing and backing up.Wondering if battery problem is related to safety switch.
My trans also has been leaking clear fluid and makes a whining noise.I can't find a filler hole on it.

Gary Heres one for ya Push in the brake to start mower runs fine for 20 min's or so. Then after it gets put under a load ,ie going up a hill, the shift lever kicks to neuteral and the mower kills. push in brake again and when you let it out the mpwer dies again. and wont restart for some time. Called local dealer he said check seat wire,spark plug and coil. any other ideas? thanks Gary
Richard Todd I've had my Scott's 1642 since 1999. Deck welds have broken twice. Hydrostat seems to be working fine maybe a little more whine than a new one. Spindles are still tight and smooth. I grease everything every time I mow. I put about 100 hours a year on it and I don't baby it. I figure I've got a 300-400 hour mower that lasted 1000 hours. Can't complain too much. I looking at the JD Z445 when this one quits.
Tom V I have a s1642 and the drive belt broke. I purchased a new one and am having a difficult time installing. I have the diagram but was wondering if someone would please post a "step-by-step" installation listing to help us non-mechanical people. Thank you.

carmine cant find where to check trans fluid level also where is the filter Its makeing a grinding noise fwd and reverse please help thanx
Russ Anyone know where I can get the discharge tubes for the bagger ona Scott's S1642 riding mower?
David Latham I have been rebuilding these transmissions for 4 years. Don't be talked into buying a new one for $600 - $900. Basic rebuild starts at $185 plus shipping both ways. Get in touch by emailing to:

cory the teeth to my scotts 1642 riding lawnmower's steering are ground down to the point the steering wheel just spins without turning the tires. I pulled the steering shaft out and both parts were worn down , How can I find new steering shafts? any help is thankfull..
Re: Scotts s1642 Hydro Transmission

I am so glad i found this page. i fix mowers and just ran into this problem on a scotts. my shifter lever is loose and the trans is coverd with oily grass clipings. i am sure my pin has worked loose and the trans is leaking and probobly low on oil as well. thanks for your help everybody. and thanks lee. i will try to post info on small problems i figure out so i can help folks as well. i will also let you know what i found. I found this pic online when i was installing a new belt on my mower. i figured i would install a new one after i found the original belt was torn to shreds due to the top lips wearing off several of the plastic idler pulleys that hold the drive belt, this pic helped me a ton.

Re: Scotts s1642 Hydro Transmission

well, after tear down. I found my rear axel was full of oil , the filter was clean, the oil was clean, and the pin is in place as it should be. so i guess that means my pump has crapped out. it will hardly move when put into forward or rev and it makes a terrible grinding and growling sound while it is trying to move. Anybody have a clue? or a direction i should go next? - I think i am about to tear this mower down and sell off the parts. anybody need a deck? i am in DFW texas.

Emil Clelland I hope you can shed some light on my Simplicity with only 258 hrs on it it is acting the same as the john Deer would go for about 10 min. then stop till it cooled now it wont go at all tuff torq wont give me any inf said to contact dealer.
Todd could someone help please?

1642h new drive belt starts up runs great take my foot off brake it dies engage blades dies with foot on brake as well
I just bought used cleaned carb new battery and one v-drive pull and drive belt

johnVr4 I think I found the problem!
John Deere Parts are made in Russia~
and for the Transmissions made by tuff torq, JD cant get parts for, or fix, only replace. For Tranny problems dont go to Deere as you'll just get a shrug and a HUGE estimate.
Example: new K51A from Tuff Torque $594 still a rip, John Deere wants $725.
I have a Sabre 1646 and it could have three different trannys K51, K51A' or K55 and they cant tell anything by the mower serial number. Save some time, get the ser# off of the transaxle directly then go to Tuff Torq site for parts. or look for used etc. If you ask me, both the JD mower and TT tranny are garbage under the name Sabre. Always run away from a Deere!

Bearclaw Todd. check your seat sensor. i have fixed a bunch of mowers with the exact same problem. almost always a seat sensor. check and make sure it is plugged in all the way, then push it on even tighter. maybe remove and install the plug a few times to get a good connection. some of the newer seat sensors have a tricky plug. it will also keep the mower from starting if you try to cheat and unplug the sensor. The seat sensor can cause the motor to cut off when the clutch is let out or when the deck is engaged.


Andyman Bearclaw, Hope you haven't scrapped your machine yet. Your problem is the fan pulley on top of the tranny. It is made by JD and it is a softer metal than the pump shaft, so the teeth inside is worn out and therefore makes that terrible noice when trying to spin the tranny pump. A $20 problem. Now if you pulled the tranny open already you might end up with some other problems after putting it back together. But if you didnt just order the fan pulley at the JD dealer and you should be fine.
Re: Scotts s1642 Hydro Transmission

Andyman, Thanks for the tip. I already have the transaxel torn down. I checked the teeth on the Pulley/ fan assembly on top of the trans, as you have suggested. after removing the pulley. I found the teeth to look great and be in good condition. I am lost. I am a ASE master tech and I have built automotive automatic transmissions for years. So, I thought I would find something inside the trans assembly that would lead me to a cause for failure. I see nothing wrong. so I started searching the web. from the research I have done on line. I have basically narrowed it down to a bad trans pump. the shift selector pin is in place and functioning, the pulley teeth look good, the oil level was full, the trans filter was clean and i found no broken or missing linkage. O well, I it Gave it a try. 5-21-10 Thanks

Andyman Bearclaw, I am still willing to bet its your fan pulley. My old one is slightly worn so that it appears ok, but its not. When you turn it with your hands it will turn but when the pressure from the engine turns then it slips and make that loud noise. Well I got mine running again like new, I had to change the Center-Case that sits above the pump assembly, because once there is some wear it is difficult to get the machined surfaces to mate and build the pressure necessary to power the unit. When the new part arrived had i known i would have tried resurfacing the center case first because the wear was not that deep. Trust me on this..i think its your pulley. its only $20 you have to loose instead of buying a hold new tranny or mower. I know you pulled open the tranny but if you never removed the center case you should be in good shape, just use 5/50 synthetic 2.5 qurts back it there.
Albert I have a Scotts 1642. I have had trouble with the drive belt staying on the rear pulley.(pulley with the white plastic fan.) The belt either breaks or comes off. I looked at the pulley with the fan and it appears to be way too much play in it to hold the belt on or power the motor. Is it possible the pulley is worn out and letting the belt slip off when put in a bind? How much trouble is it to replace the pulley or even find the parts?
Andyman Albert, I don't think its your fan pulley that is losing the belt, but rather one of the other guide-pulleys near the fan-pulley. Make sure those are tightened on straight. The fan pulley u can order from your local JD dealer, it will cost about $20, and 4 days. Look above at Bearclaw's picture showing the drive belt.
Dart What fun.

Same symptoms, noise and little power, going forward and back. Got worse the same day, finally, mostly not moving at all.

The pulley on top of the hydrostatic transmission is the problem. Yes, it was slipping. The "E" clip that retains the pulley and the plastic cooling fan that moves air over the aluminum fins allows the pulley to move up and down on the shaft.
The result is that the pulley eventually wears the splines away, on both the input shaft and itself.

Doubtless, the input shaft is connected directly to the pump.

The design of this is that, as soon as you begin using the tractor, the needless wear starts, and gets worse every time you use the tractor. This is a designed in flaw.

*IF* the pulley had been secured with a nut on top, this never would have happened.

I am going to braze the pulley directly to the shaft, as it appears to be made of iron. Hopefully, this will secure it for whatever the rest of the life of the tractor will be.

If you want to properly check your pulley, you must release the belt tension. With the tension on it, it appears to be solid. When the belt was released, the wear was apparent.

It is possible that metal weld or JB weld or some similar compound *might* make a permanent repair. But vibration might cause a failure.

I expect that replacing the pulley *only* might serve for awhile. But if the input shaft is worn, it will rapidly wear again.

There is little or no excuse for this sort of sorry engineering. Doubtless, John Deere will not pay for it out of warranty. But it is sloppy and careless engineering here, because the pulley is not made of some soft zinc or cheap metal.

Pulling the transmission is a removal of a few nuts and bolts. No problem if you are slightly handy with tools. I suspended the tractor with a come-along a few feet off the air. Tie rope around the transmission to secure it from falling.

The noise it made: Obnoxious whining chattering noise, that got worse with more speed. Also, climbing up the driveway, it slowed down and made much more noise under a little pressure.

Bearclaw Andyman, Thanks for the extra info. I will take a closer look at my pulley and shaft. I got the S1642 for free, so no loss. I have already removed the trans and completely disassembled it to see how it functions. maybe the exploration will come in handy on a future project. after waiting weeks for a response. I searched the web for help and this was the best site and info i have found on this mower. I had the mower tore down right in the middle of my shop and decided i needed to move it out so i could get profitable projects moving. I tried to turn the pulley by hand while on the shaft and it does not seem to have very much movement between the splines. looks to be functional. so I decided to part it out. I sold off the parts online and have made quite a bit of cash just on parts. The motor is awesome and will come in handy soon enough. I am Thankful that you have taken such an intreats in this site. I will take a photo of my pulley and shaft. and post it for you to see. you can possibly tell me more after looking at it. (I am with Dart, if I could do it all over again. i would have put JB weld on it just to see if that was the problem) John deere quality, what a load of crap. I get better service from MTD. Low bid or what?

Darryl Glad I'm not the only one. Mine mows good and moves along fine but as soon as you start to go up a slight incline it crawls and almost comes to a complete stop. Once your over the fill it moves along good until the next hill comes. Anyone out there know pretty certain my trouble. Please help.
Andy I NEED TO RELACE THE GROUND DRIVE BELT ON MY S1642. This post stream has been very helpful and informative, but how do I get the belt around the pulley on the engine shaft. Anyone with a step by step on the belt relacement process? Thanks in advance.
gary my scotts brand mower 16hp by john deere will not move when you depresss the clutch it dies also the gas tank will leak out through the air filter i think its flooding the engine any ideas?
Bearclaw Andy, look close in the previous posts for more info. I will try to Help. First of all remove the deck if you have not done so. its a wast of time trying this while the deck is installed. You will have to remove the parking break leaver that pokes up through the floor board, remove the large tensioner spring and I think a piece of the steering linkage is in the way of installing the belt. Put the belt on all pulleys and then install the large spring. if you are trying to install the belt onto the motor pulley last it will be much more complicated. when installing the large tensioner spring after the new belt has been installed. use a set of vice grips and stretch the spring into place. sometimes it will slip and cause you to bust your knuckles. so wear a pair of good gloves and get er done. while you have the belt off it would be a great idea to drop the idler and tensioner pulley. check to make sure both spin easily. you can buy a grease needle that attaches to the end of a grease gun. (aprox $3.99) using the needle you can stick it into the bearing at the seal and pump a few squirts of grease into each bearing. this will insure you will not have to worry about a bearing failure. its not a lot of fun to deal with a drive belt of pulley. so its worth the extra trouble to do it right the first time. If you decide to grease the pulleys, poke the needle into the upper bearing seal on each bearing. this will insure that if a seal is slightly damaged it will be on the top side of the pulley. and it will not leak grease. It is very simple to do. and iv never damaged a seal . if the seal pops up while greasing. just push it back down with a screwdriver or your thumb.
bearclaw gary, sounds like the needle valve and seat are allowing fuel to pass through the carb. This is usually caused by a stuck float, or a float that has a small hole in it allowing the float to fill with fuel and then it will not lift up to shut off Fuel flow. Most common is a Needle seat and needle valve not sealing proper. sometimes removing the carb and giving it a nice cleaning will fix this problem. DO NOT remove the spark plug and try to turn the engine over to clear the fuel from the piston. If you are not careful. it is easily possible to ignite the fuel blowing out of the motor with the loose spark plug or wire. Its best to change the oil before you run it, because the fuel also leaks down past the piston and contaminates the oil. running the motor with fuel in the oil can cause catastrophic damage. --- also sounds like your seat sensor is causing the engine to die when you let the clutch pedal out. very common problem. push the seat sensor on as tight as possible. take it of and reinstall it a few times to clean the connection. if its the seat sensor, it will also die if you try to engage the deck while sitting with the engine running.
Paul Does anyone know where I can get the electrical diagram online for Scott Lawn Tractor S1642?
Robert My scotts 1642 mower is leaking a small spot of oil.This is coming out of the tran. near the rear axle(left side)what kind of oil.and where do you you check and re-fill,Thanks
Ken How do you get the cap off the trans to check the oil/refill?
Ken Rob,
I am new to this but, you have to drop the transmission after removing the rear wheels. Not hard to do - only 7 nuts and bolts and one cotter pin. But, I haven't yet got the oil fill cap off - just started my little project after the JD dealer confrimed - $700.00 for a new trans!

Ken OK, so getting the oil cap off is easy. Just pry it up.
Now I need help. My Trans was screaming and no go. I opened it up and the tranis practically dry. I am not an expert so I am looking for help. Do I refill with oil, reassemble and hope that was all it is or do I need to tear this thing apart??

Larry Thank you all for sharing your knowledge. I was able to get my transaxle serviced and my tractor up and running with the info provided by all of you. Especially the point about filling the oil tank with the spring and filter removed. It looked full until I reached in and pulled them out.
keane thanks you guys -just replaced the tranny pulley and it works great -no more screetching.

Scott I purchased this same mower a couple years ago. IT has been nothing but a PAIN in my rear. The pulley's are plastic and will wear out quick. I've replaced 2 or 3 drive belts now. The same for mower deck. The starter has been out for 2 years so I'm using a screwdriver to cross jump it manually. I thoroughly HATE this lawn mower. I wish someone would take it off my hands. It's nothing but fix, fix fix. I know for sure, I will never buy a Scott's, John Deere product ever again!
Karen Rich I am having the same issue with my Scotts tractor. I have tried to locate this pdf. file online and am having no luck. I would love to see page 10 so that I can fix my tractor. Any advise? Thanks
Ihan John Deere use to have the parts manual online but I tried to locate it the other day and failed.. They like to change up thier website a bit... It had a diagram of every possible part on the 1642...
Ihan Ah ha, found it... John Deere website, parts, search catalog by model, then the tricky part for me, right under the yellow start searching here marker hit john deere parts catalog... type in s1642 and browse away... any part you need and where it goes...
FranksRig gotta tell ya! I had the drive belt break on my 1642 and i went to Advance auto parts and bought a 96in vbelt for 19.00 and it worked great!
MK Does anyone have a diagram or a picuture of where the saftey switches are located. I seem to be having a problem starting the mower and it is related to the saftey switches, I just do not know exactly where they are on the mower.
Steven I have a Scotts mower 1642 and need to check the wiring schematics. It will run for 5 min then just die. I brought a new ignition plug I am now trying to hook it up and having trouble wiring it. Ready to throw it to the curve. Thanks Steve
Outskirtsdweller Would just like to say thanx to those who took time to post their experiences on here. I picked up a scotts 1642 from a neighbor that just wanted it out of his garage because the transmission was making a screeching sound and would hardly move. He had already bought a new big green jd....After reading through here, I removed the transmission (not that tuff to do) and found the pulley on top was waaaay too loose on the shaft...very sloppy fit. Since the tractor was a freebie, I cleaned everthing up and just JB Welded the pulley to the imput shaft and let it sit over nite. Reassembled and fired it up....Dang thing is super smooth and runs/pulls like a top even with my 220# self on board. All is good as long as the jb holds up....thanx again....
Homer I need the diagram of the transmission belt, it is off and I need to replace it.
Thomas I have been looking for a solution for a year, thanks for the info. Will tear mine down next week to see what happens. Noting ventured, nothing loss.
chuck Can anyone tell me where all the bolts are to remove the transmission from my S2046? It does have the K51a tranny, i have already spoken to tuff torq about parts. I have a new pulley for the top of the shaft in case that is the only isue, and i have the oil to change once i get this thing pulled from the mower. I have a tech manual on cd for these ,pwers, but have mis placed the dang thing. I have replaced the drive belt numerous times i the past and have mailed it to many others.
Thanks ahead of time. Chuck

Dan Does anyoneknow where I can get a copy of the K51 manual? The site Lee posted ( is not up. I'm very happy I found this site. My S1642 is doing the exact same thing Lee described. I'm going to pull the transmission this weekend and would like to have the parts list in hand. Thanks for the help and encouragement.
David I have a Scotts 1642 H and the unit will move slowly forward or backward and make a sqealing noise when trying to go faster. After removing the mower deck, and old drive belt I can see the trans pully with fan blade wobbles and appears loose. Based on some people using JB Weld to resecure, I want to know where to put the JB Weld?
Rustybolts Hey, guys, don't feel bad, have a scotts 1642h 2000 i think and have replaced that gear under the plastic fan 3 times already cause thoses splines stripe away; no bad to replace, but feel lucky for having found the problem, i hope the next problem is not the tranny cause that will be the end of the 1642
Re: Scotts s1642 Hydro Transmission

Scott, check your idler pulleys. the idler pulleys need to be greased every 100 hours or so. and as the idler pulleys have no grease zerks, they need to be removed. pull the deck and lay under the mower. take one pulley off one at a time so the belt stays in place. with a grease needle from ACE or auto zone you can grease the idler bearing without causing damage to the seal. while the pulley is out check the plastic pulley for unusual wear. If the bearing is bad or the pulley has a worn place the belt will wear out much faster. with the info I can get from your post. it sounds like the starter is working fine. if you can jump the posts and make the starter engage, it must be working or it could not start the engine. It sounds to me like the $10 starter solenoid has gone bad. if thats the problem, its much cheeper to fix. Pick up a new starter solenoid at your local auto parts store. most auto parts stores keep the basic riding mower parts in stock.
Also, John deere mowers including the Scotts and saber that are actually build by john deere are awesome mowers. They usually run twice as long as MTD and AYP junkers. The main problem with the 1642 series talked about on this message board is trans-axel related. tuff torque is to blame. In my opinion hydrostatic transmissions are problematic and have a shorter life span. the old manual gear selector style is the way to go. I pull manual shift transmissions out of old craftsman's and Murray's and put them in new mowers. they will outlast the mowers twice.

Re: Scotts s1642 Hydro Transmission

Steven - A very simple reason this could happen is a blocked air passage in the fuel cap. the tank will pull a vacuum because it cant allow air in, if the hole in the top of the fuel cap is plugged. As the tank pulls a vacuum it will not allow fuel to flow out of the tank. this even happens on gravity feed systems. if the cap is good try replacing the ignition coil. sometimes the coil will work fine until the motor warms up. once the coil gets hot the coil will short to ground. possibly due to the metal and coil expanding when hot. Possibly a crack is becoming exposed when it warms up allowing the coil to short to ground. then your engine looses spark and will not run. - any other ideas? i like to learn too.

TerryG My JD 1642 has been running well for 4 years. Recently when I engage the cutting blades it make s a louder than usaul noise... Bearings or such... I haven't seen a thread on this problem.. Any solutions??? Thanks in advance.
Bearclaw TerryG - Yes, its more than likely your bearings going out. Most of the JD mowers have grease zeros on the desk spindle housing. its a good practice to grease the mower atlas once a year or else you will begin experiencing failures. i think on your mower, you should find the grease fittings on the upper part of the housing located on the top side of your deck. lower the deck down as far as possible and clean the grass of. sometimes they are hard to see. if your bearings are already making noise. it is probably to late to fix the problem with grass alone. but it could prolong the bearing failure and keep you mowing for a while. replacing the bearings is a very simple repair with the right tools.
Re: Scotts s1642 Hydro Transmission

A few good mowers

lawrence waibel I need a diagram on how to put transmission back togeter. please help.I took mind a part and can,t find anything on how to put it back togeter.
will My problem was exactly like stated in Mark Harpers post above. Broken spring, scored mating surfaces between pump and motor. I had hoped that it would be the obvious pin backing out as mentioned above, but instead have about 150 in parts to purchase.
Richard, Epp Anyone know where I can get replacement bagger tubes? The lower tube is broken where the lock pin is located. Can I get one?
Gents, after reading all the great comments I opened the K51 trqansmission on my S1642. Nothing seems loose or out of place. I replced the belt pulley and fan and 2 1/2 quarts of oil. My question is when I turn the belt pulley and with the rear rod engaged should I see the axels turn? It seems the mower would not move before if the rear rod was engaged. Can someone advise if I'm missing something. Thanks.

Ncname With David's expert advice I was able to replace the fan and pulley after opening the trans case and finding nothing wrong. My S1642 is running like new again thanks to David. davidlathamjr@hotmailcom

John Dix I have a Scotts 46" 19hp tractor. The model number is 46572x8. Cannot find any number starting with an S. Consequently I cannot find any manuals for this number. Bought the thing at Home Depot in about 1998-99. John Deere should be ashamed of buildin these pieces of junk. Can anybody help with the model number problem? Thanks, John
Allen I have a 38" cut Scotts and experienced the same tranny problem as some described. The experts told me most of the hydrostatic transmissions were sealed. However, I removed the battery compartment under the seat and looked in with a flashlight. I found two rubber plugs that I carefully removed and filled the two compartments with hydrolic fluid. Put the plugs back in and the mower has run fine for about two or three years now.
David G My lea bagger on my S1642 says in the manual it is for a 38" or 42" mower deck. All I see online from John Deere is the one for the 42 or 48" one that is square. Mine is ROUND. I need a new bottom section because the one I have been using for 10 years is all chewed to pieces from slipping out of place while mowing. What a crappy design. The Deere Dealer here told me a new bottom would cost $90. That is OUTRAGEOUS since the whole bagger was $200. Anyone know where I can get this round one at a decent price. I think the Deere dealer is trying to rip me off. 8/20/11
John M I just drove a few hundred miles to pick up a 1642 that has the no-go/wining symtoms described above. No energy to dig in too much tonight, but wonder if someone can tell me what it takes to get at the top pully. Is it sufficient to remove the plate under the battery, or must I drop the transmission?
John M After struggling to get everything removed to drop the transmission, I decided to work (struggle) to remove the steel plate that is under the battery instead. It was worth it since I can see that the fan pully is very stripped. Even after all the comments that were posted, I could not believe my eyes when I saw how fragile this critical component is. Now, I am in search of the part. I'll post a picture and the part number this week.
John M The replacement pully described in the posts above is part number M127358. Price was $13.75 from local John Deere parts counter.
Wayne Thompson I've got a Scott's 1642 mower that I bought in 1997 and the only trouble I've ever had with it, until now, is starter solenoids and batteries. Considering it's always stayed outside and only been serviced one time, I'd say 14 yrs within 15 miles of the coast is not a bad life. One of the lift supports has come loose because the mower deck rusted out. I'm going to patch it up and make it a 15 yr life then I'll replace it with one of the Z-Traks since I have a lot more to mow now.

Something I wanted to point out, my Scott's has a full operator's manual, 63 pages, located at the back of the mower, up underneath the body, out of sight unless you're laying on the ground. It's in a clear plastic tube with black end caps and I only took it off 1 time in those 14 yrs, till now. It's pushed up into 2 spring clips and it will not fall off and I'd be willing to bet money most everyone of you have one because it was factory installed.

BTW, a new mower deck shell is $400 or $600 with all the pulleys and bearings installed from JD.

Wayne Thompson The only reason I found out that the mower support had come loose, is that it wouldn't start and I looked and saw that the only deck belt that's ever been on it, had worn so badly that it jumped the pulley coming from the engine. I got a a new belt, GX20072 and new blades, GY20850 and then pulled the deck off. That's when I found the rusted deck and loose support. Once the deck was off, the tractor started right up.

I've never had any problem with the transmission and don't have any plastic pulleys anywhere. The shift knob top half came off as I parked the tractor but I epoxied it back.

One of the idler pulleys is noisy but it's been that way almost from day one. I'll trust it to finish the season. If I ever come across a used deck, I'll put it on for a spare but the tractor will pull a trailer or drag just fine. And I'll use my 4120 JD and 6 ft bush hog to mow the roadside and my new Z-Trak (when I get it next year) for everything else.

I live in an area now where there isn't anything but JD tractors, from the biggest to the smallest. You're looked down on if you have anything but green.. ;-)

David G. My 1642 Scotts mower,,bought in 2000 from HD won't go forward or backward when the hydrostatic lever is advanced. It moves real slow but then you hear gears squealing and no it won't move. I immediately tuned it off and pushed it into the barn. I see other posts here suggesting the cooling fan pulley, a pin that has worked itself loose etc. This happened with no warning. The tractor always jumped suddenly when engaging the transmission if you are not careful and move the lever too fast. Could this be a bad pump. The fan does spin , I can see it spinning while in neutral. Thanks for all the ideas I gleaned from other folks with the same problem. Sounds like built in obsolescence to me.
David G. Thanks for all the info on the Scotts 1642 Hydrostatic Transmission. I will pass on my experience. My tractor stopped moving when advancing the transmission throttle and it just whined and squealed. It would barely crawl along on the slowest setting. I ended up removing the transmission by jacking up the tractor and removing the 6 bolts that hold it to the frame,,unplugged the wire harness on the right side of it,removed the nut that connects the throttle handle,,and removed the cotter key to the brake linkage on the left side. Took the belt off the drive pulley under the engine to be able to take it off the transmission pulley. I did not even take off the tires and rolled the transmission out the back. Taking the tires off would make it easier to reinstall everything though, as I found out when trying to put the throttle link back in place and put the nut on. A tight squeeze between the right tire and that linkage for hands. The PROBLEM WAS: A bad pulley. The splines on the inside of the pulley had stripped. The shaft splines were fine due to a harder steel. The pulley , part # M127358 was available at my local JD dealer for $15.02 plus tax. A snap ring is all that holds it onto the shaft. Remove the 2 bolts holding the fan on,,slide the 2 pieces off the shaft, There is a bushing above and below the pulley and fan that just slide off also. Replace the pulley and reinstall the fan/pulley on the shaft. Reinstall the transmission. I did NOT remove the spring on the tension pulley. After the belt is on all the other pulleys use a crow bar of long rod from the LEFT SIDE under the tractor to push the pulley back far enough to have someone else slip the belt over the tension pulley. You are now DONE. A $15.00 repair and you are back in business. If the shaft is damaged I am under the impression it is only held in by a snap ring also and slides out of the transmission so the transmission does not have to be opened up to replace it also. Good Luck.
David G. I found the lower chute available through John Deere for $64.00.
Big Al Looking for removed s1642 Hydro Transmissions.

I am looking for a couple of s1642 hydro's remove do to functional issues.

Located in michigan

Big Al

Olcott Burke About to replace the drive belt on my S1642 when I noted the pulley with fins on top the trans has a wobble to it of maybe a quarter inch all around..Im wondering if this is the way its supposed to be. I havent dropped the trans to get a handle on this, but it seems like that pulley/ shaft shouldnt have that much play in it.
Olcott Burke Ive gotten deeper into the problem and note..the pulley seems a bit loose from the shaft, from what I have read here its not the best design..but it is what it is but the splines seem to still engage the shaft..and the shaft seems firm and tight, no wobble.
I pulled the battery out and found a small black plate covering above transmission and was considering if I unbolted and lifted that plate assuming its possible to do so, if I wouldnt gain access to the top of the trans where the pulley is??
I sure wish this had happened back when it was warmer.

Roy E. Salsbury I have a 2001 Scotts S1642 today it stopped pulling forward or reverse. The drive pulley
on the transaxle isvery loose and is wobbling.
I replaced it about 5 years ago, it is splined
and the splines wear out,thou the nut stays tight. the pulley last time cost around $16.00
take out the 4 bolts on the transaxle jack up the rear of the tractor,remove nut and pulley
then replace with new one Roy Cibolo Tx

ccassani Thanks for all of the go info - same problem with my Scotts S1642 and now armed and ready to repair.
Lyle I have an S1642 and the trans is doing most all the same stuff loosing power and grinding after a while of running. I just dropped the trans today and found the pulley everyone is talking about has already been welded to the shaft. Everything looks ok inside the trans, so anyone have any ideas?
dave HI I have a kohler powered by john deere: model s1642 riding lawn mower. Its a very easy fix, take off the transmission, its very easy 6 bolts in all, the pulley is your problem and maybe the shaft.The noise is from the shaft and the pulley rubbing together from a little wear, and when you add power to the tractor, it has no power and the pulley and the shaft rub together and make the grinding noise.You can ether weld them together or buy a new shaft and pulley, will cost you about 60-70 bucks, I welded them for long time use,lol.If you have another model, it might be the same problem. Hope you fix the problem.
Rick This thread has been very helpful for me so I hope my success story helps someone too. My S1642 would move forward and reverse for a couple of minutes, or until an incline, then stop. After it stopped you couldn't get it to move again, but if you let it sit there for 30 minutes it would move again. No grinding noise as referenced in other posts, just wouldn't move. I took it to JD and they told me the trans was gone and I was looking at $925 to repair. NOT putting that kind of smack in a lawnmower (but that't just me).

So I read this thread and decided to at least look inside the trans to see if anything was obviously wrong. Removing the transmission was easy enough. Cracking it open I noticed the fluid level wasn't at the 2.5 quart level mentioned here and there was quite a bit of sludge. So I drained the old oil, wiped out the sludge, resealed it with Permaflex Black and let it sit over night. The next morning I filled it with 2.5 quarts of 10W 30 and put it back on the mower. Guess what...mowed two lawns that morning (one in a vacant lot with 6" wet grass) and a week later I haven't had any problems with it mower.

I went back to JD to ask WTH and the service manager told me that they used to offer what I did as an attempt to repair trans problems but they stopped because it didn't always work (due to bad pumps inside the trans) and customers would get upset. So JD feels it's better to tell me it's shot and $925 is required rather than tell me to spend $22 on oil and Permaflex to troubleshoot it.

So my take away, if your hydrostatic transmission won't go forward and backwards once the oil gets warm (and you're not hearing grinding or knocking noises) then you're probably low on oil or the oil is old and needs to be replaced...

Johnathan I've got the 1642 with the stripped spline problem. I am an engineer (actually got this 'cause I worked on the tires they used on it) and without any formal analysis of the problem I'd say that the problem lies not with the tolerances of the parts, but with the lack of anything to secure the pulley other than a clip. If it had a set screw or was bolted on, there would not be movement of the pulley relative to the shaft and wear would be minimized.
I've ordered the new shaft and pulley ($80 with shipping), but in the meantime I've fixed it by cutting the heads off sewing pins and pressing the pins into the space between the pulley and the shaft all around. It takes most of the play out, and gives the splines something to grab on. If I wanted to make the fix permanent, I'd JB weld it and see how long it lasted, but I think it will be easier to remove the shaft if I can get the old pulley off!

One more thing. The person who was having a problem with the engine stalling whenever he took his foot off the brake or engaged the blades almost certainly had a bad safety switch in the seat (operator presence sensor). I had the same thing happen, and ended up bypassing it (I know, bad idea) I guess I should have ordered a new one when I ordered the pulley...

Dale This is an excellent thread for the Scotts S1642 Tuff-Torq K51 hydrostatic transmission. Thought I'd add my two cents. First up front, most but not all, John Deere dealers still have a chip on their shoulders over Home Depot and Scotts teaming up to produce and market this lawn tractor, which they felt was cutting them out of sales opportunities. Hence you get dealers commenting when calling them that the tractor is a "throw-away" unit or the hydro-transmission is sealed for life and not serviceable resulting in $600 to $800 estimate for replacement, all designed to get you into their shop to buy a higher end expensive unit. Truth is the unit is highly repairable and very dependable when used and maintained as originally designed. My tractor had failed with the same issue many post here after ten years of use. As an Engineer I'll tackle anything and did in this case.

The first thing everyone should know is the tractor is not design for use with "Ground Engaging Implements", i.e. snow plows, pull behind aerators, De-thatchers, etc. My bad was loaning the tractor to a neighbor to aerate his lawn. The tractor had been used for over ten years mowing my half acre lawn without one problem which included traversing a 30% grade. The one use as a De-thatcher caused the Hydro to fail both forward and reverse. My opinion is that some internal wear was present but with the low viscosity factory motor oil 10W30 it couldn't take the load causing extremely high heat and additional hydro component wear. That said it was time to tare this thing apart. Yes it's a little work, but the payback is well worth it. After removing the transmission getting it in bench position, I opened it up to find nothing obviously broken or out of place. Oil was not burnt or highly discolored.....hmmmm. I called Tuff Torq service tech support Derrick Dalton (423-585-1977), who helped me develop a two method approach. First change the oil, which many times will fix the problem without further issue, and second buy only the high wear parts and replace them if my first approach failed. After a thorough cleaning inside and out, I upgraded to Mobil 1- 20w50 oil to compensate for internal pump/motor ware. As a preventative measure I did replace the fan/pulley spline attached to the input shaft and a new drive belt. The spline did show some ware but not severe. The tractor is running well today at 12 years old, and I don't plan to purchase another in my life time. Derrick gave me a list of internal components that are the high ware and the heart of the hydro-drive, so I bought them as a back-up for future use. I'll place them in a oil bath for use sometime down the road. Those parts are the: Pump kit p/n 168T2025090-$58.13, Center Case A p/n19216824500-$88.45, and Motor Kit p/n168T2025080-$71.00. One last item at about year 7 or 8 I noticed the transmission was producing an increasingly louder whining noise when climbing a grade, that became barely audible after the oil change confirming the higher viscosity oil was doing it's job.

Moral of this comment: Don't listen to your local John Deere dealer, odds are they're lying to you. Service your Hydro-Transmission oil at the 175-200HR mark and you'll be a happy camper with your, "Throw-away Lawn Tractor".

Harry Millican Fellas I have found this very informative&Ito have been repairing my Churches scotts 1642&I would probably have to agree with you that there are some design flaws which could've been corrected had they wanted to bad enough,but why do that because they can give you some tech advice that does'nt hold water&it will drive you batty if you let it,however there is some good news,my son&my boss&I found the mower deck drive belt size&diagram online at Outdoor Power Equipment,Small Engine,Lawn Mower Repairs,Troubleshooting&Repairs or try hope this will help ya'll& I too am having to pull my trans drive pulley off becauseI don't want to have to tear into it again so I'M replacing the pulley &the trans drive belt but checking to make sure the input shaft turn's properly first thank's for your info&trust mine will help other's over &out.
Re: Scotts S1642 Hydro Transmission / Tuff Torq K51A

Thanks for everyone's advice - saved me hundreds of dollars and a lot of time! After 10 years and 406 hours (with a self-installed meter) I experienced the screeching / grinding / scraping noise problem with my John Deere / Scotts S1642 riding mower whenever I engaged the transmission in forward or reverse. My mower would move slowly, but if I tried to gain any speed, the grinding noise started and the tractor stopped.

As with many posters here, I discovered the cause to be extreme wear on the hydrostatic drive's input pulley and input shaft. The spline mating surfaces on the ID of the pulley and on the shaft OD had both worn so badly that the pulley could spin freely (albeit in a chattering way) on the shaft. When I was driving very slowly, the belt pressure held the pulley up against the shaft enough that friction and what was left of the teeth would turn the input shaft. At higher speeds, the torque overcame the grip between pulley and shaft and the pulley release and ground around the input shaft.

I solved the problem by removing the Tuff Torq K51A transaxle (just put the rear hitch on a cinder block and a piece of 2x4, pull off the rear tires, disconnect two linkages to the tranmission, remove six bolts and it's off!), and replacing the pulley and input shaft. Total cost for new shaft kit, new oil, and a new pulley was about $100. Time to complete the repair was about 4-hours once I had all the parts.

I ordered the replacement Splined Input Shaft (Part #19216899490 - called a "Pump/Bearing Kit - K51A, B, E") from Derrick at Tuff Torq (actually I got advice from Derrick - Phone: 866-572-3441, and ordered the parts from their web site - - The Input Shaft Kit consists of a splined shaft, a seal, and a spring [the spring is a new improvement and was not part of my original K51A.] The kit cost me $25.00 plus shipping.)

The replacement Pulley (#M127358) I got from my local John Deere Dealer for about $15.00.

Replacement of the Input Shaft is easy and is accomplished without opening the case! While working on the transaxle, I took others' advice and replaced the oil in the unit with Castrol 5W50 Synthetic Oil. On Derrick's recommendation, I just popped the big oil cap off, removed the spring and filter, then inverted the K51A on a 5-gallon bucket to drain. NOTE: Derrick says to NOT invert or move the K51A while you have the input shaft removed as components inside can shift! I drained mine before changing the shaft. Changed the shaft, then filled with 2.25 L of 5W50 (should fill to just above the filter.)

The new spring that goes on the input shaft required some fiddling to get down into the hole.

Be sure to purge the air from the transaxle after refilling it with oil. I failed to do this and at first I thought my repair had failed. Instructions for purging air can be found at the Tuff Torq link above - under the Tech Info link in the lower left corner. After I drove the mower in a slow, herky-jerky fashion for a few minutes, things smoothed out and now it runs as good as new. Now that it's purged I will recheck my transmission oil level this weekend.

Re: Scotts S1642 Hydro Transmission / Tuff Torq K51A

Photo of Tuff Torq K51A Input Shaft Kit - Part# 19216899490 - I got it from - $25.00

Re: Scotts S1642 Hydro Transmission / Tuff Torq K51A

Spline on Old and New Input Shafts for K51A Tuff Torq Transaxle

Re: Scotts S1642 Hydro Transmission - John Deere Splined Pulley

Photo of worn John Deere splined pulley and new splined pulley - John Deere Part # M127358

art violi help ive bought three belts now all wrong from my local parts store scotts model 1642 h drive belt anyone know the lenth and size?
GTO Bearclaw DEMower, Thanks for posting the detailed photos and descriptions of your process. this will make it simple for the future visitors to this site. It takes valuable time to give advice. finding the failed part is a big issue, but you have made the rest of the process simple. now when folks find this thread. they will have everything they need. (Now, if they would just read the thread completely before asking the questions that have already been answered)

Thanks again for the time and dedication to help your fellow man.

rick How did you get the old shaft out? I have tried prying but it isnt budging.

Jay Sundquist I just had my tranny give out and it will be investigated today. Thank You for all the Great Info! On the Plus side when I bought it in 1998 I put an hour meter on it and it has had 24,052 Hours on it since I bought it and it is used to cut 7 Family Members Yards and only work done to it has been Scheduled Maintenance and it has been Awesome! This is My Baby! I hope it is a simple fix.

william kosloski How do I check the oil in my transmission, do I haft to pull out?????
Gary To all:
I have had this K51 transmission out of the my circa 2000 HomeDepot JD tractor now about 6 times in attemts to fix the spine problem and also the $300 internal kit to replace the pump etc. I fixed it myself with a lot of help from this page!!! It's now running great again. If you want to e-mail me, I've learned lots of tips and tricks on how to fix this habitual problem. It's do-able !!!!

Lee scotts 51a won't move... had JD pick it up..called and said the tranny was shot and they wanted eleven hundred dollars to fix it...I'm going to take it apart and see what i can find..I'll check all parts ...tuff tourq want 600.00 for a new tran.
Nate Just purchased one of these ( S1642 ) partly because of the front axle which looked pretty beefy compared to box store tractors. Name J.D. had nothing to do with the purchase, it fact I was a bit leery to the really cheap units at Home Depot and Lowes. I wouldn't call them J.D.'s either.

One thing I hope you guys are doing is to drill and tap a drain plug and filler hole when you rip the trans out to do repair work. I'd add some good full synthetic oil when filling up and maybe it will last a bit longer. Also if you have a small leak you have to be able to put oil back in right ? Geez that's really poor engineering...unless they want it to fail so you buy another.

Dan hi, i had the power train transmission belt
on my s1642 burn off because the pulley by the fan (not the fan)froze. I put a new pulley on it and now I have no idea how the belt goes. Does anyone have a diagram. The only one I could find shows the pulleys NOT in same order as my s1642. The picture of the tractor is the same as mine but the pulleys are all different. thank you

tlmolder Same problem as some of the folks above.
Drive pulley worn, caused input shaft to wear.
Ordered parts from TuffTorq - $25 + shpg.

My question is how do I get the worn input shaft out of the housing?
I have removed the seal at the top.
Removed the snap ring holding the bearing in place.
I can't get the shaft to move.
Don't want to "persuade" it too much as the case is cast alum.

darrellhanson scotts 2048 the safety equip like seat, pto, cluch. how to these items out because my scotts will do noting!
tim i have a scotts 1642 it needs a tranaxle will a scotts 2046 transaxle fit mine is a K51A the one i want to install is a K51E
John M I just finished replacing my 2nd pully. This time, I ordered and replaced the input shaft kit as well. I will summarize a few things that I learned from Derek and while doing the job.

1) When dropping the transmission, be careful not to break blades off the fan. (Just saying :)
2) Be sure to remove the single electrical connection.
4) Be sure to remove the free-wheel rod from the bypass lever on TOP of the transmission.

5) Put a mark at 2.5 liters on an old milk container. I emptied the old oil into this container so that I knew how much drained.

6) After removing the black rubber cap and spring from the oil inlet/outlet, drain the 1st 1/2 of the fluid with the filter in place to avoid getting any dirt past the filter. Once you remove the filter, drain the rest being careful to avoid letting the fluid get into the section previously protected by the filter. This may not be critical, but it makes sense to me. The bulk of the fluid drained after removing the filter. By draining my pan into the milk container, I could tell that all 2.25 liters had drained.

5) Stab the black rubber bushing with a pair of nose pliers or a pick and pry it out.

6) You will see two retaining rings under the pushing. The one that you must remove is an "internal" type that sits in a groove just above the bearings (not the C-clip). A pair of retaining ring removal pliers is convenient for removing the retaining ring.

7) I was able to put the old pully back on the shaft to twist and pull the old shaft out. It did not take much coaxing once I had that little biut of leverage.

8) The new shaft has a spring that gets installed over the bottom of the shaft. Per Derek, put a little grease on spring to hold it on the shaft while installing the shaft. Also put some grease on the new rubber bushing.

9) **** Install the drive belt while the transmission is being bolted in. I found it very difficult to install the belt otherwise.

10) The purging of air was not as big a deal as I expected it would be. I followed the procedure with the wheels off the ground, but I am not even sure it was necessary. The only thing I have some doubt about now is that the tractor seems to lunge forward when going from reverse to forward. Less so when going neutral to forward, but more than I remember it doing so before. Good Luck.

Tom s Have a1999 Scott's s1642. (Kohler procommand 16hp) Just replaced transmission input shaft and pulley; worked great. Then changed engine oil and cut grass. Noted oil down on mower deck. Oil appears to be leaking under engine. Are there any gaskets on bottom of engine? How do you remove pulleys from engine shaft to pull engine? Thanks.
Roddey Howard I would like the price of the noted shaft kit above. 19216899475. Thanks
Mike Crigger I had the exact same thing happen to my tractor! I have never messed with a transmission before, but tried to fix per these instructions. Everything in here is spot on. Part numbers, etc are all still the same. Only thing I can add is I had to put vise grips on the old shaft and tap it out with a hammer, then tap in the new shaft while moving the axle back and forth for it to go in the groove.


Mike Crigger I thought my tractor was not worth the repair bill but found this post. This was EXACTLY what was wrong with mine as well. Followed your post to the tee, this is spot on. Part #'s, everything is absolutely correct. Only addition is I had to put vice grips on the old shaft and lightly tap it out with a hammer. Then tap in the new one, while twisting the axle back and forth to ensure it lines up in the right spot. My tractor is back, better than ever, super tight, smooth, etc.
Thank you VERY much DEMower!!!

Art I had the same problem (limited torque, screeching noises) except I carefully aligned and welded the pulley to the shaft (grass grows fast here in Wisconsin). The trans. still slips a bit when warm, on slopes so I'm looking for a service kit (drive seals), new pulley and drive shaft to finish the repair right.

Thanks for posting, the web site link will be very handy.


Bill Pippin I had a hard time extracting the input shaft from my unit. I gripped it with vise grips and tapped on the shaft with a screwdriver. Started out well, then stopped. I pulled a little harder until the unit was off the table an inch or so. Then, it let go and that little fall dislodged the swash plate that the input shaft fits into. So, I had to open it up. After I saw what had occurred, I knew how not to do it again. I have never seen this piece of advice, so I wanted to ensure that it hit the net and maybe someone could be spared the frustration of turning a 15 minute job into one of several hours.

The trick is to secure the "control lever" which is part number 86 on the Tuff Torque breakdown. Push the lever toward the case-mounted switch until it touches the plunger and depresses it just a little. Then do what you have to do to keep it from moving...I used a tywrap. Empty the fluid and remove the seal and shaft. If the control lever doesn't move neither will the swash plate and the shaft will be in alignment and you don't have to worry about movement from an unintended shift of components. Also, if you screw two 1/4" or 5/16" self tapping screws into the seal, it will pull right out. Just place the screws 180 degrees apart.

I hope this helps someone. I just wish I had known. I called Tuff Torque and I was told not to try and move things around trying to get the swash plate to re-align. He said I would do far more harm than good. After getting inside, I saw what he meant. Spring loaded pistons(at least one) will exit their cylinder. They are mated to their own cylinder, so you run the risk of a problem there. If you just render that control lever immobile, you're home free.

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