Tuff Torq Loss of Power – Tips to diagnose and repair

Replacing Worn Cylinder Blocks and/or Center Case

Is your transmission experiencing a loss of power or no drive when it reaches operating temperature? Diagnosing issues with power loss on your hydrostatic transaxle can be a daunting ask.  As always, we recommend that you seek the expert opinion of your local service dealer in these situations.

Finding the Root Cause for Tuff Torq Loss of Power

However, if you want to take care of the issue yourself, here is some helpful information.  In a majority of cases, a loss of power in a Tuff Torq hydrostatic drive system can be tracked to one root cause. It is likely that the cylinder blocks and center case need to be replaced.  If you need to repair this issue, it is critical to replace all components. This would include 2 cylinder block assemblies with new pistons and springs, and the center case. If the cylinder blocks or the center case has damage due to wear, then related parts will also.  If all parts are not replaced, it is very likely that you will have another failure within a short time.

There are many misguided blogs on the internet that say you can save money by not replacing all components.  This may be true in the short term. However, it will result in drastically shortening the life of the parts. Therefore, causing a situation where you are doing the repair again much sooner than necessary.  At this point, you cannot simply replace the components which you avoided in the first repair, as they will be damaged and you will still have to replace them to properly repair your unit.

We offer a complete repair kit that includes the center case, cylinder block assemblies and all gaskets, filters and sealant required to complete the repair. Genuine Tuff Torq repair and replacement parts are available on our service site here. If you have questions, please contact our professional service team here or by phone (866) 572-3441.

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  • James Hoegger says:

    Need to know more about a tuff torq trans axel in a 1994 john deere 245. The numbers #056700 by kanaki

    • ggraham says:

      That is an old transmission that is known as a Saur/Sundstrand. We no longer have parts for this unit so you will need to see if John Deere has parts.

  • Kevin Turner says:

    I have a Simplicity 20hp Broadmower with a K57 A 0008994 trans. It wines when engages and looses power when warmed up.It seems that it is loosing fluid by looking at the casing oil and grass buildup on it.. It also has very little braking power. Is this transmission rebuild-able???

  • Fay Leverkuhn says:

    I have a Tuff Torq Transaxle, 787Q0824000, S# 7D-L0051838, came off of a Z425 EZTrak Zero-turn. This is the left side. Do they make a repair kit for this Transaxle? The mower does not turn to the left. It would work for a short time only. Checked the oil level in the transaxle and it was a little low on oil. Added oil but still only worked for short time. I opened the casing and everything looks good. So I suspect it’s the pump. Need a part number if they have a kit. If they don’t make a kit, what is the part number for transaxle? Thanks

    • ggraham says:

      We do have a repair kit which will replace the pump, motor, center case and you also get a seal kit. The Part number is 187Q0899500-7L.

  • Craig Thaler says:

    I have a John Deere LX 277 I believe it has your 62 trans. I need a quote on a rebuild kit for the pump motor section

  • Jody rodrigues says:

    I have a torq k51a transmission that is barely moving. Can you quote me on the price of the rebuild kit please?

  • I have a AS 800 FREERIDER with no drive after a couple of minutes.
    Gearbox is k46am.
    Please can you give me a price for a rebuild kit.
    I will buy it.
    Many thanks

    • ggraham says:

      The part number is 1A646099581. You would need to order it from the distributor for your country. I do not ship to countries with distributors. For the UK the Distributor is Uni-Power.
      Unit 8, Flitch Industrial Estate
      Great Dunmow Essex CM6 1XJ
      e-mail: info@uni-power.co.uk
      Telephone: 01371 875331
      Fax: 01371 874777
      Web site: http://www.uni-power.co.uk

  • Dan Clark says:

    I can’t get my 4500 craftsman riding lawn mower to go forward or backward .
    Can you give me some tips
    The tractor does not want to move at all .

    • ggraham says:

      First, check all the external things like the belt and all the pulleys on the entire tractor. Next check the linkages make sure they are Moving like they should be and are not broken or bent or bound up. Next, if your transmission has a shock absorber on the rear hooked to the control lever, try unhooking it and trying to mow without it. They can sometimes keep the control lever from travelling its full arc. If everything external is correct then it is an internal issue and you might need to open it up to inspect the parts. If you have any other questions you can contact the service department at salessrvc@tufftorq.com or 866.572.3441.

  • Tom Price says:

    I repaired a K-46 transmission in a John Deere X300. The bottom pump bearing failed. Got parts and put back together. Now the tractor is slow in forward and fast in reverse. What did I do wrong?

  • James Madore says:

    7A646084321 S/N 46CR0050040
    HOP PN : 426121
    Please supply a price for a replacement right axle shaft.

  • Pat DeRosier says:

    I am looking for information rebuild kit and instructions for repair of tuff torque from lt180 john deere.

    • ggraham says:

      We in the service department need the serial number off of the transmission bar code sticker. armed with the serial number we can get you the part numbers and pricing.

  • Michael Nix says:

    I need a rebuild kit with instructions for the transmission on a 2008 husqvarna yth 2348. There are numbers on the bottom of the tufftorq. They are k46 IA6460 -24168 Please respond.

    • ggraham says:

      that number on the bottom is the part number for the lower case. there should be a bar code sticker on the case of the transmission close to one of the axles that you can normally see from the rear of the tractor. get the serial number off of that sticker and I can help you.

  • steve mills says:

    What about this – can anyone shed light?
    My mower, with the K46 transaxle, won’t allow me to let up the clutch without stopping the engine. I’m assuming there must be something wrong with the axle, but could there be something else wrong? Any suggestion gratefully accepted!

    • ggraham says:

      if it is pulling down the engine I would think you would want to inspect all the pulleys. If it is not that then it must be something in the transmission.

  • Matt r says:

    Hi can you help , have a 2009 husqvarna pf21,while in use front axle seized up , only had ( forward) drive in rear wheels ( no reverse ) has ktm 10 and k66 , which axle should I look to repair?? Thanks Matt

  • Max Jones says:

    Hi can you advise me on the following.
    I have a powerless k55 on a countax ride on mower. I’ve been offered a k46 to replace it. Can you tell me if it will fit. Thanks Max.

  • Geir Ove Hafstad says:

    Hi. I have a K92 in my John Deere x748 4×4 with hyd driven front axle. Drive pedal, kontroll arm or swash plate recistance and vibration, not always but with load or high steering angle. Traktor feels strong. 700 hours. Where to look? Control arm damper is ok. Its not recisting when it of the ground.

  • Geir Ove Hafstad says:

    JD x758 4×4 with hyd driven front axle. Drive pedal, kontroll arm or swash plate recistance and vibration, not always but with load or high steering angle. Traktor feels strong. 700 hours. Where to look? Control arm damper is ok.

  • Al greco says:

    Why is it tuff torq does’not put a oil drain pulg on some of their transmission?

    • ggraham says:

      The Transmission is built to the specifications set down by the Tractor manufacturer. If they want Drain bolts and request drain bolts then we install them.

  • daniela venhaus says:

    Can I replace a Tuff Torq K51 with a Tuff Torq K51A? It’s for a John Deere LTR166!

    • ggraham says:

      the K51 designation is series of transmissions. the K51A is a specific model of K51. So to answer your question I need to know which K51 you have. There should be a bar code sticker on the case of the transmission close to one of the axle and if you find the serial number that will tell you which K51 you have.

  • Jeff Barber says:

    I have a K46BT in my Husqvarna mower that over time started going slower and slower until it finally stopped. I’ve pulled the transmission off and have it opened up and all the gears look fine. Not a whole lot of debris on the chip magnet so I’m thinking the issue is with the hydraulic pump / motor.

  • Dray Dillard says:

    I put a camera on the frame of the mower and when I depressed the pedal on hills the transmission whined and the belt and pulley stoped moving until I let up on the pedal. I just put 3 new tires and other parts on this sucker! Any advice would be appreciated. Thank you.

  • Dray Dillard says:

    I have a Johndeere lt180 with a k46 transmission in it. It does fair on flat ground but will not pull its self up hills at all. It whines loudly on hills then the transmission pulley stops spinning. I drained the fluid and it is lightly brown in collor and very thin. The mower has 774.5 hours on it. When the trans slips the rear wheels and foot pedal vibrate and when you press the pedal more in just kinda klunks then makes no noise at all.

  • M Sills says:

    My 2018 John Deere E140 has the K46. It has a forward & a reverse pedal. If I press the forward pedal a little,
    it goes forward slowly. If I press the forward pedal all the way, it goes forward faster.
    Am I damaging the K46 by pressing the forward pedal a little ? Is it like riding a clutch?
    Does this cause the K46 to run hot?


    curious in Crescent City, Ca.

    • ggraham says:

      When you push the pedal on the tractor it moves the linkage which moves the control lever. The control lever moves a part called a swash plate which rocks in a cradle in the case and squeezes the pistons in the Pump cylinder block. By squeezing the pistons it forces oil through an orifice in the center case which then is directed to the Motor cylinder block and the oil pressure makes the motor cylinder block spin which then turns the motor shaft. The motor shaft turns the reduction gear and on it goes till the axles turn. You can understand what is going on in this the whole system with an explanation so you know then that the oil pressure is really running the tractor. So if you push the pedal a little it squeezes the pistons a little and puts through only a small bit of oil pressure and the tractor goes slow. If you push it all the way and the oil is really pressured, it then makes the tractor go faster. No damage is done becaseu it is designed to be run this way.

  • Vangelis Rounis says:

    ATV JCB GROUNDHOG model 2006 KT 35 serial 000070??
    Suddenly the shaft got stuck
    The gear selector( thick ring) is stuck. What are the recommended parts to be replaced.
    Thank you

  • Roger Bailey says:

    I replaced the pump and motor in my K66 to fix the loss of power, After I reinstalled the transmission reverse is fine however forward is week. almost feels like the pump is cravitating or loosing oil. the longer I run it the worse it was getting.

    • ggraham says:

      It now would be a good time to check all the externals including the shock absorber on the control lever. You would need to unhook it and run the tractor for a while and see if it is stronger in forward. also, check the Keys on the axles and hubs. Two good places to start troubleshooting.

  • Brad Morgan says:

    I have a John deere LA 115 I’m trying to figure out if I have to much play in my belt and it’s slipping or if I need to rebuild it. Can you tell me how much play the belt is suppose to have please. The mower has lost power and won’t pull itself up and incline at all.

    • ggraham says:

      That would be a better question for John Deere. I do not get to see these in the tractors and a John Deere service tech should know tension on the belts.

  • Patrick mcnally says:

    Hi who is my Tuff Torq distributaries in Uk please. Thanks Patrick

  • AR Warrena says:

    My Husqvarna dealer said tractor has a K46BT it turns out it is 57R which I discovered when changing to syn oil. Problem was not solved with the new oil. There is still a long delay when trying to go forward, but no delay in reverse. If I hold the forward peddle down it will eventually start to mover and attain normal speed. 144 hours and 5 years on the tractor only used for grass cutting no winter operation. Does Tuff Torque offer a rebuild service, does it have a recommended rebuilder, does it offer refurbished units?

  • Brian says:

    I have a JD LT180 with a K46C with about 700+ hours on it. Recently it started losing power on hills, checked the drive belt and it was heavily worn and damaged. Replaced it and mower ran good for about 3 cuts (approximately 7.5 hours) and then power loss began again. It got to the point to where after about 30 minutes of cutting I had no power to go up a hill. I pulled the transmission, and changed the oil, 1 qt of 5/50 and 1 quart of 5/30 synthetic oil, at the time I thought it only took 2 quarts, so I know I’m .25 quarts low now. There was a little very fine material on the magnet under the drain plug, but no large pieces. I cleaned up the magnet and reassembled everything, but got the same result, 30 minutes of cutting and all torque was gone. I do smell some burning rubber, and the drive belt gets extremely hot, is this normal with a failing transmission? Or do I need to be looking at something else?

    What advice would you give me to go on from here?

  • James Cardinale says:

    The transaxle on my simplicity region says 46Z I assume it’s a K 46 I was going uphill heard a sprawling sounded like a spring broke now in forward and reverse it just makes a raspy squealing noise . It feels like it wants to move but it doesn’t . It’s a 2006 Simplicity regent It ran fine up until I heard that sproing noise.

    • ggraham says:

      That is a strange noise and not one I can easily assign a problem too. It is probable you will have to open up the transmission to determine the problem.

  • Nathan says:

    I have a K46 it will not move either fwd or revirse.I rebuilt with new kit still nothing or at best moves very slow in either direction.So whats next i have pulled this transaxel out so many times i should get a job with tuff torq !

    • ggraham says:

      For issues like this, it is important to check everything that could be affecting movement. The pulley on the engine could affect the belt which in turn affect the transmission operation. Also, check the pulleys on the tractor. A broken bearing could have an effect on the transmission. The pulley on the transmission should also be inspected to see if it is turning the input shaft. The linkage is also a needed check to see if it is bound up or bent or broken. It could make the control lever not move in its full arc which would then seem like the transmission could not move but it is really not building enough pressure. You should make sure the oil level is correct. It probably is but check it again. Make sure you have bled the air out of the hydraulic system by going through the bleeding process. And the last thing to check is the keys on the axles if it has them. if one is broken some strange things could happen to the transmission. If after all that if it is still not working you should contact the techs in the service department at 866.572.3441 or email at salessrvc@tufftorq.com to find out what your next options are.

  • Eugene Burma says:

    I have a John Deere Scotts product GX2554s012948 Model 2554.
    The transmission only works for a very short time. I don’t see a filter on system. Is one inside?
    What are my options? What should or could I do to further see what is possible to fix and costs.

  • preston williams says:

    I have a Scott’s 2554 with k-66 Transaxel. works fine on flat ground but not on hills. what do you suggest.

    • ggraham says:

      I would suggest changing the oil in the transmission. 5W-50 synthetic motor oil, ours being the best with a part number of 187Q0899000. The K66 holds 2.5 liters.

  • Adam says:

    I have a cub cadet xt1 enduro series
    With a k46 it will not go forward or backwards no noise or anything. It only has 34hrs on it. Any suggestions?

  • Robert Percifield says:

    Ive had it apart 2 times for axel replacements so im familar with it. I figured its time for a new transmission vs a rebuild. What are your thoughts? I dont know if i could tell by looking what the problem is.

    • ggraham says:

      That is entirely up to you. You would have to weigh the costs and aggravation needed to work on it as compared to just getting one ready to drop in.

  • Robert Percifield says:

    I have a 2554 husq with k46 aw.
    Gets slower the longer i mow and no reverse on very slight slope, engine seems too be running hot. I changed belt and found the fan on trans hard to spin. I assume its not supposed to be hard to spin by hand?

    • ggraham says:

      There should be some resistance but not a lot. It is unfortunate but you would need to open up the transmission to find out exactly what is wrong with it.

  • Peter says:

    Something happened with my K46 transmission. It’s noisy during accelerating and the acceleration is slower. I’ve changed oil but it didn’t help. What should I check or repair? Thanks

    • ggraham says:

      You would want to inspect the Center Case and both Cylinder Blocks. Paying particular attention to the metal surfaces between kidney ports on all three parts. You are looking for scoring scratches or anything that is not smooth.

      • Peter says:

        I’ve found the root cause. The oil filter inside of gear was fully dirty. After cleaning transmission working as before. The issue was that the cap from oil reservoir was lost and the oil get dirty. Is it a special cap or simply bland the reservoir?

  • Ken herrington says:

    My k 46 transmission is slipping and no power where can I get parts live in Ontario Canada

  • TROUSSELLE says:


  • TROUSSELLE says:

    Bonjour ,
    Qu’elle est la procédure pour remplacer arbre de pompe sur transmission K46C.
    Procédure for replacing pump shaft in K46C

  • DAVID HAY says:

    Bonsoir je voudrais savoir combien couterais la trousse de réparation complète pour une k46 qui va sur un tracteur tondeuse toro N74590 seie 210000395 . Merci de votre réponse

    • ggraham says:

      First off you would need to contact your distributor in France. Then, they would need the serial number of the transmission to get you the correct parts.
      Crosnier SA
      Route de Boullion
      Bonnelles 78830
      e-mail: info@crosnier.eu
      Telephone: 011-33-1-308848
      Fax: 011-33-1-30413159
      Web site: http://www.motoculture-crosnier.com
      Countries Served: France, Portugal, Spain

  • Joe Pittiglio says:

    hello, i have a scotts/jd S1642 with the k51-A transmission. it started screeching and would barely move. i pulled the transmission and opened it up. changed oil with 5/50. all gears looked great. then after i put it back together i realized it was only the pump shaft and pully that had worn splines. i ordered your shaft kit and a new pully from jd and replaced them, no problems there. now the tractor wont move. i was only able to fit about 1 and 3/4 qts of oil. i went thru the bleed process with the wheels off the ground. at first they barely moved, now they wont move at all. i am going to drop the tran again to check the oil level. , all linkage is hooked up correctly. any ideas on what i need to look for when i drop the trans again? exactly how is the bleed process supposed to be done. thank you in advance for any info you can give.

    • ggraham says:

      That transmission holds 2.25 litres. So if you do not have close to that amount of oil in it it does not have enough oil. Try pulling the filter out that sits in the bottom of the fill area. It should allow the rest of the oil to flow in.

      • Joe Pittiglio says:

        Thanks so much, i removed the filter and was able to add much more oil . Works perfectly now. Regards…

        • ggraham says:

          That is excellent news.

          • BobbyBD42 says:

            It seems everyone on this thread keeps saying they added quarts when the spec is in liters. 1 3/4 quarts would be like 28 ounces out of like 73/74 that it requires. I would think this would cause significant damage if so. We are all used to any kind of oil to be in either quarts or gallons but He must mean 1 3/4 liters right? I’m not confused right?

          • ggraham says:

            a liter is a little bit bigger than a quart so you can easily translate liters to quarts by adding a little to the amount. For example, 2.3 liters translates to 2.4 quarts.

  • Stan Edwards says:

    I have a husky 2654 it wouldn’t pull about 15 mins and quit took the cover off , after removing rear unit it was almost full of water , k46 , which was not supposed to be in a garden tractor , I need the seal kit for this unit. , I found a hole in the seal on top , all gears and pumps seem to be fine , pistons and springs seem to have plenty of pressure , I need to get this unit going been down almost a year now , every is at odds on what oil to use !

  • Thomas Duren says:

    I have a k46 that the wheels will turn with the bypass lever pushed all the way in. When it is jacked up off the ground the wheels will spin but can be stopped by hand wont move on the ground.

    • ggraham says:

      It sounds like there could be wear on the hydraulic parts. You would need a repair kit which will replace those parts. Please contact the service department at 866.572.3441 or email at salessrvc@tuftorq.com with the serial number of your transmission and they will be happy to assist you in getting the part you need to return your tractor to new.

  • Frik Du Preez says:

    Im having transmission problems with my baron ride on mower. I ve had it repaired and it ran beautifully for about 30mins until the power to the wheels slowly dried up and i was fortunate to get it back inside. On inspection the following day there was an oil puddle formed under the transmission area. Its a tuff torq k46q S/N: 46q-0002549, SMPL P/N: 1721022 according to the badge on the sticker. Im relatively capable and would like to get it back operating if I knew I could reasonably repair the issue. Can you advise.

  • raymond says:

    after rebuilding k 46 gearbox .and fitting back to the ride on it happens funny thing..when i engage drive lever to go forward it goes backwards,and opozite when to reverse it goes forward ,rideon is honda 1211.any sugestions

    • ggraham says:

      Hello Raymond,
      You have inserted the motor housing in wrong. It needs to be flipped 180 degrees. The motor housing is usually wedge-shaped but can be a box with a built-in wedge. Once you flip that housing forward will then be forward.

  • jackie cress says:

    i changed the oil , i replaced the belt , same results , i went in to it only to find parts missing , according to parts diagram the model number is 7a646084100 is this unit suppose to have a torison in side where the control arm is because there is not one there , .i don’t see where any of the parts are really worn out i just see a few parts missing according to parts diagram , i talked to a technican and he said it was k46 ba and they don’t have those springs

    • ggraham says:

      Your technician is correct, the K46BA does not have a torsion spring on the control lever internally. It has a different system that is all external. If you have any further questions about your transmission you can always talk to the helpful techs in the service department by dialing 866.572.3441.

  • jackie cress says:

    i have a craftsman dys 4500 with a tuff torq k46 transaxke it does not pull good in foward unless i pull the pedal back with my foot mit has a new drive belt on it , i changed the oil ,,, but still have the same problem it’s even slower in reverse ,, any suggestions other than a bad transaxle

    • ggraham says:

      Changing the oil in the transmission is a good first step in troubleshooting a sluggish transmission. We recommend a 5W-50 synthetic motor oil be used. You can get the best oil for your transmission right off of the Service Parts website: http://www.tufftorqservices.com. When removing the transmission from the tractor you will be in a good position to check the linkage And the fan and pulley to make sure they are functioning properly. As always you can call tech support at 866.572.3441 to get all your questions answered.

  • Kevin says:

    Hi I have a sears lawn tractor and there is a bearing type noise in reverse it not if I push a little pressure on the pedal .Also I don’t see any fluid in the reservoir and how do I service the transaxle I also see a cap on the case?

    • ggraham says:

      Hello Kevin,
      I would recommend that you change the oil in the transmission. After the purging of air in the system you should check to see if the issue is better. And remember you can always call and discuss this with a tech in the service department at 866.572.3441.

  • Shane Kennedy says:

    I am having trouble with a K46DF transmission on a Husqvarna ride-on mower. I replaced the thrust bearings on the hydraulic motor, the old one had disintegrated. Now, I can go forward (weakly) when the front box is disengaged and backwards when the back is disengaged. I am fairly sure that the hoses cannot be switched. Not surprisingly, a loud whirring noise is generated by the disengaged box through mechanically back driving the gears and motor. It is a friend’s mower, so only occasionally get over to look at it.

  • matthew hough says:

    Regarding Tuff Torq 7A646024041 S/N: 46E-0045394 (UK Countax 478000301)
    This is the 3rd time i have had to replace this failed hydroelastic drive transmission on a Westwood lawnmower (approx 2002) due to power failure forward and reverse after grass cutting for about 15minutes.
    I cannot afford to keep replacing this item.
    Can you let me know cost of complete repair kit and/or new replacement complete part for the above trasmission.
    If I replace the whole lawn tractor with newer version is the updated hydroleastic transmission likely to have similar problems after eg 2-3years.
    This has been the main failing of my lawnmower.
    Thank you.

  • Steve Smith says:

    My transmission quit working while mowing. Upon teardown everything looks good except the filter is plugged. I’m having trouble accessing your website. I found a different phone number, I’ll call that.

  • Kim Boggs says:

    I need to get this kit: We offer a complete repair kit that includes the center case, cylinder block assemblies and all gaskets, filters and sealant required to complete the repair. Can you please advise the cost. Thank you!

    • Hi Kim,

      We’ll be happy to help! The best way to insure we get the right repair kit for your unit is to call our expert service technicians and have them review your issue and recommend the parts you need. You can call our toll-free number at (866) 572-3441 or visit our service website at http://www.tufftorqservices.com . When you call, please have your serial and model numbers off your transaxle so that we can quickly look up your unit and help you with the parts you need. Have a great day!

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