The Dreaded Tuff-Torq K46 Hydrostatic ******

[B.S.A. (ret.)]

Hi! I'm happy to join this forum, which is covering a topic I have spent much time and some money on. I have looked at several other forums, including the official Tuff Torq site about the K46 transmission, which my JD X300 tractor has.
That's because, like many others, I have had frustrating issues with it, and never found a cure.
This tractor has 408 hours on it now, and I use it to to mow the lawn and snowblow my driveway too.
A couple of years ago, it would no longer go up the steep part of my yard. So I looked online, and got lots of information, but not the cause that I discovered.
I did remove, drain and refill the trans, as advised (with Castrol Edge synthetic 5W/50), and that worked for a while.
Bottom line is, all other information did not include this:
Oil leaks from the vent when going up steep hills. After a while, it will whine a lot, then eventually, will not go uphill.
I did not realize at first that it was unnecessary to pull the trans or remove the top of the tractor to fill the transmission through the fill hole. Simply removing the vent plug was sufficient; saved a ton of trouble and time.
All the problems I had that were what others had, whining, weak, not going, were caused by loss of oil. All of them were solved by adding oil.
I read every comment on Tuff Torq's forum, and never saw a mention of this, or on any other forum. So many people spent much effort, dismantling the units, rebuilding them, enduring great frustration. I was frustrated too!
Seems like it leaks oil faster now than it did when new. Maybe the vent is supposed to maintain some minimum pressure, and gets tired over time. I may try replacing it, but I already have a fix brewing in my head: an extension which raises the vent plug, so it still vents, but at a higher level, so the oil won't leak when going uphill.
I don't see why that shouldn't work.
I can't be the only person who has thought of that, can I?
I will update this forum with the details when I figure out a good way to do that.

Tuff Torq must have made tons of money selling replacement units, when there was nothing seriously wrong with them!

McGee:

Are the cooling fins plugged up with accumulated grass and debris? Have you checked the fan for proper operation and/or damage? It could be overheating and venting the oil out the vent cap. Another thing is you mentioned that you snowblow your driveway with it. My understanding is that the K46 is neither designed nor recommended by the manufacturer for use with "ground contact" accessories. You may have inadvertently damaged your unit by using it in that manner. Not criticizing, just trying to help troubleshoot.

 

[McGee]

Hi bpjr,
I haven't tried that, but I reckon it would just blow out the vent.
Somewhere I think I read that the tractor was not intended to be used on a grade steeper than 15 degrees, but the dealer didn't tell me that. My yard has a slope on it much steeper than that, and lots of people have hilly properties. VT ain't flat!
Anyway I'm not figuring on overfilling it, just keeping what's in it from spilling. I hope it works. Worth a try!

 

[McGee]

Hi B.S.A (ret.) Yeah, it's clean. Actually I replaced the fan, because I didn't have the snap ring on tight the first time I did this, and it went flying. Got a replacement from ebay, unfortunately the wrong kind (black, fins set to rotate the other way). So I got another replacement, and I have been conscientious about keeping it relatively clean.
Funny thing is the ebay seller pictured the correct fan, and when I told her she did not send me the one in her photo, she said she got it from a Deere dealer who was shutting down, and he told her it didn't matter, just tell me to mount it upside down!
But the pitch of the fins and their plane were different, and I knew it would not cool as well as the correct one, so I got to keep that one for free. Anybody needs a black fan here, you can have it for shipping cost!
I bet dollars to dognuts my fix will work, though I don't want any dognuts! I promise, if this fails, I will let you know, too. I appreciate this forum, and the sharing of useful information not always found from the official sources.

 

[finn]

McGee:

Are the cooling fins plugged up with accumulated grass and debris? Have you checked the fan for proper operation and/or damage? It could be overheating and venting the oil out the vent cap. Another thing is you mentioned that you snowblow your driveway with it. My understanding is that the K46 is neither designed nor recommended by the manufacturer for use with "ground contact" accessories. You may have inadvertently damaged your unit by using it in that manner. Not criticizing, just trying to help troubleshoot.

The torque required to run a snowblower wouldn’t go through the transmission, so the snowblower wouldn’t be considered ground engaging equipment like a rear plow , etc

 

[B.S.A. (ret.)]

The torque required to run a snowblower wouldn’t go through the transmission, so the snowblower wouldn’t be considered ground engaging equipment like a rear plow , etc

Not necessarily true in all instances. A steep, hilly property during a Vermont winter might tax the capabilities of that transmission depending on the weight of the snow and how much resistance force (weight/depth of snow x degree of slope). From personal experience with a walk-behind snowblower, I can attest to having to force the machine into drifts/banks when dealing with a heavy, wet snow.

 

[kelpaso1]

The torque required to run a snowblower wouldn’t go through the transmission, so the snowblower wouldn’t be considered ground engaging equipment like a rear plow , etc

No but it takes some considerable power through the trans to push that snowblower through the snow. While a blower on a lawn tractor works pretty good, you are working that trans alot harder than cutting grass.

 

[McGee]

Not necessarily true in all instances. A steep, hilly property during a Vermont winter might tax the capabilities of that transmission depending on the weight of the snow and how much resistance force (weight/depth of snow x degree of slope). From personal experience with a walk-behind snowblower, I can attest to having to force the machine into drifts/banks when dealing with a heavy, wet snow.

It is true that the snow causes a lot more resistance than grass does! But I don't think it hurts the transmission. The wheels will spin before the tractor stalls, though the snowblower can stall the engine if it's jammed enough, in wet, heavy snow. That or the belt slips, but I don't let that happen, because that kills the belt. Anyway the driveway isn't as steep as the grassy hill. The loss of drive happens when mowing uphill.
I did have a new idea for a possible fix though, to keep oil from leaking out the vent, and I'm going to try it. That is, to swap the locations of the filler and vent plugs. I ordered a new one of each. I'm going to see if I can cut a hole in the filler plug, fit the vent into it, and put it in the original fill plug location.
Then find a plug/cap to go in the original vent location, since the hole sizes are different.
That way, going uphill the oil can slosh to where the vent normally sits, and stay in the transmission.
After all, both the filler and the vent plugs are above the same space, no pressure difference, but the oil will not be up against the vent when going uphill. I will report how that works out. Seems like it ought to work OK. Can't help thinking the designers of this transmission knew full well that having the vent back there would cause leakage, unless the vent was designed to hold some pressure (from the air in the transmission heating up) but gets weak over time.
Perhaps a test, using a pressure source, a low-pressure gauge, and comparing a new vs. an old vent plug is in order.
After all, it seems this was no problem when the tractor was new for a few years, now it happens all the time.
It does seem that, from seeing oil on the grass I've mowed on the steep slope, that it does OK for a while, then a bunch of oil comes out all at once. So either the pressure builds up for a while, then the valve opens, or it gets hot, and can't hold the pressure.
Anyway I will get to the bottom of this. I used to do testing like this at work, so I think I can conduct a sensible, documented test of an old vs. a new vent plug.
Still, why did Tuff-Torq put the vent at the rear rather than the middle of the transmission, and why the fill plug in the middle, where, if you didn't know that you could add oil through the vent plug hole, you have to go to a lot of trouble, either removing the top part of the tractor, or else remove the transmission, to access the fill plug?
Looks like it's there for rubes like me to be snookered, and give up or take it to the dealer for an otherwise simple job, if I didn't have the mechanical ability (or gumption) to do it myself.

 

[Bigblockyeti]

Still, why did Tuff-Torq put the vent at the rear rather than the middle of the transmission, and why the fill plug in the middle, where, if you didn't know that you could add oil through the vent plug hole, you have to go to a lot of trouble, either removing the top part of the tractor, or else remove the transmission, to access the fill plug?

Planned obsolescence.

 

[Compact7]

First Post! This thread brought me to GJ, joined to view the pics. (and abuse the emojis)

Looking at a Cub Cadet new from the local dealer. I guess it has the TL-200 trans which seems to be a step down from the K46. Forewarned is forearmed, as it also does not have owner check or fill access.

B.S.A., if you happen to read this, do you have an "after" pic at hand, showing the drain and/or fill ports you added? Merely curious, I'm not an avid youtuber, no need to shoot a pic just for lil' ol me! TIA!

Oh, here's a couple pics of what I'm mowing with now, a 1973 Sears Compact 7. It's a little "Edified" here and there, as we call it, but it's still workin' after 47 years of use and abuse.

-Ed

 

[B.S.A. (ret.)]

B.S.A., if you happen to read this, do you have an "after" pic at hand, showing the drain and/or fill ports you added? Merely curious, I'm not an avid youtuber, no need to shoot a pic just for lil' ol me! TIA!

Here is Tuff-Torque's instruction photo:

 

[Compact7]

Thanks much!

 

[Tostal]

Hi B.S.A. (ret),

Would it have been possible to just remove the bottom cover plate with the trans. still installed in the mower, in order to drill, tap and fit the 2 drain plugs?
(would save a fair amount of dismantling and possibly struggling to remove the rear wheel hubs).

Can you recall the thread size of the drain plugs you installed?

Re:- oil leaking from the vent? when used on slopes?

My trans has a little translucent plastic reservoir tank mounted on top of the transmission. It's topped-up by removing a plastic plug on top of it. The instruction manual says to only top up to 1/2 way on the tank (there's a max. line) as the oil will expand in use....

Iirc, this reservoir tank simply fits into a grommet on the transmission to hold it in place, (it just clears the cooling fan). Maybe, 'McGee' could check with TuffTorq or a mower shop and see if this reservoir tank is available and if it could be fitted to his trans?

T~

 

[B.S.A. (ret.)]

Hello Tostal.

I'm not familiar with your model of Tuff-Torq transmission, but if I removed the bottom plate on my K46, all of the internal components would drop to the ground. I believe that the plugs that Tuff-Torq sent me were M10-1.5 (or possibly M12).
The K46 does not have an external reservoir, I check the oil level by using a scale to measure the level from the fill or vent cap seating surface. No mower shop that I am aware of will touch working on these transmissions. If pushed, they will simply order a new one and swap it out on your tractor. The cost usually is at least the equivalent of the purchase price of a new tractor.
My recommendation to you is to contact Tuff-Torq Customer Service directly (https://www.tufftorq.com/support/) as my experience with them has been nothing but positive. They will send you parts, instruction/specification sheets and offer advice on what you should be looking for while you have the unit apart.

Good liuck!

 

[Tostal]

Hi B.S.A. (ret),

Thanks for your reply.

Good to know what would have happened if I had attempted to remove the bottom cover plate from underneath while the transmission was still in situ.

My ride-on mower is made by the SECO Group in the Czech Republic, sold under the brand name LawnBoss over here (Europe). They are fitted with B&S, Tecumseh or Honda engines. The transmissions used are Tuff-Torq, if hydrostatic, or Dana, if manual. Mine is fitted with an 18 hp Tecumseh and has a Tuff-Torq K46A1 trans. (the 20 hp version has a Tuff-Torq K62Q trans.).

Some years ago, I made some enquiries and was told that the K46 trans. came in 2 or 3 slightly different versions depending on what the lawnmower manufacturer it was destined for, wanted. The base model had no drain plug(s) or filter. The next step up had a drain plug(s), the top version had a filter (possibly external and replaceable?)and drain plug(s). This might explain why my K46 trans. has a plastic oil reservoir tank instead of a filler plug.

Mine is probably the cheapest version, does not have any drain plug(s), it doesn't have an external filter, I don't know if it has an internal one (like your's), as I haven't had it apart.

Incidentally, my inst. manual makes no mention of using synthetic oil, instead it recommends SAE 10W-30 API CD oil. As regards oil level, for the K46A1 it says minimum = 1/2 way in the oil balance tank height, for the K62Q it says Mark 5-7 on the balance tank.

Thanks for the advice, I'll probably wait 'till the end of the grass-cutting season to strip my trans. - this will allow me plenty of time to do the job, contact Tuff-Torq, order/then wait for parts and deal with any unforeseen issues.

Again, many thanks,

Tostal.

 

[B.S.A. (ret.)]

Best of luck with your project sir! There should be a sticker (visible from the rear of the tractor) on the transmission case stating the model and serial number of your unit. This information will be required when corresponding and ordering parts from Tuff-Torq. I assume that you will come through this with colors flying!

 

[Tostal]

Best of luck with your project sir! There should be a sticker (visible from the rear of the tractor) on the transmission case stating the model and serial number of your unit. This information will be required when corresponding and ordering parts from Tuff-Torq. I assume that you will come through this with colors flying!

^^

Thanks again,

T~

 

[Bigblockyeti]

Has anyone swapped out a K46 for a K57R? I ask because surplus center has them for $270 and they have the same 3/4" axles allowing the use of the same wheels from the K46 axles.

https://www.surpluscenter.com/Power...Torque-K57R-Hydrostatic-Transaxle-13-1607.axd

 

[PetesPonies]

They're not all bad. I picked up a running L111 this past weekend. Horrible looking, deck needs some serious wok, but it ran . . so the transaxle wasn't toast. It had over 500 hours on it, I bought it from the original owner. In redoing the tractor, the plan was to drain the transaxle and fill with 5w50 synthetic . . .which is what TT suggests now. I drained the 15 year old oil and it was surprisingly clean. Magnet had a small amount of grit on it, but I was very happy. I think the synthetic oil will have this transaxle working for many more years. For whatever reason . . they are not all ****

 

[window]

BSA (ret) if you're still reading: I assume Tuff-Torq sends the instructions, etc, electronically. I'm about to tear mine apart. I figure after 20 years of continual use,
it could use some new oil and parts. We use it for mowing, hauling wood to splitter and then to pile, snowblowing and such. I wish I had an hourmeter on it. Anyway it won't go up a hill after about a half hour running and won't push the fluffiest of snow after about the same. Forget going in reverse without lifting the blower.

I don't want to do extra work but just draining the oil seems less than ideal. Taking it apart may lead to some needed cleaning and other indications of bad juju that can then be fixed.

I'll keep the place posted.

 

[PetesPonies]

After 500 hours, my oil came out very clean considering the age. The magnet had barely anything attached to it. It was running before hand . . not all of them implode.

 

[window]

Can't get one wheel off but if I have to there's a machine shop I can donate a little to.
I had a flat a few years back - that wheel came off just fine.

One of the 4 bolts that holds the whole mess to the frame won't come out. I noticed on one of the other bolts that there's some beige colored stuff (loctite?) that's not on the two from the other side. They came right out. These two felt like they were threaded into the transaxle body but I finally got 1 out and maybe it was just 20 years of gunk.

Finally, none of the videos I've watched have the bolts that hold the transaxle together like these. They look like a 1/4 inch torx bit. So I'd need a female end socket to get them out. Fortunately, L&M is having their 15% off bucket sale so I'll figure out what I need and get that tool.

 

[Tostal]

Can't get one wheel off but if I have to there's a machine shop I can donate a little to.
I had a flat a few years back - that wheel came off just fine.

--------------------------------
------------------

Finally, none of the videos I've watched have the bolts that hold the transaxle together like these. They look like a 1/4 inch torx bit. So I'd need a female end socket to get them out. Fortunately, L&M is having their 15% off bucket sale so I'll figure out what I need and get that tool.

If it's a wheel held on by a circlip (snapring?) and driven by a key on the shaft, the key may have worn an indentation in the keyway/groove inside the wheel bore which can prevent the wheel being removed. You might see if the wheel can be rotated a little on the shaft - if so, the key might be jamming in the indentation. Rotating the wheel in a forwards direction relative to the shaft should align things and might allow the wheel to be removed.

The socket you need might be what is called an 'E-Torx' socket and afaik comes in only metric sizes, it sounds like your's might be an E-6 size?
www.powerbuilt.com/products/10-piece-e-torx-socket-set

You could also use a 'spline drive' socket of a suitable size.

T~

 

[window]

I'm just going to buy a set of E-Torx sockets. Saw them at the store today. Still fighting with the wheel. I'll try a few more things I saw on YouTube. No rotation - it's stuck. If all else fails I can sawsall the wheel and get a new one. Seems a bit extreme but that'll be the last resort.

 

[123Go]

Hot Damn its that time of yr again!
Fwiw Ive changed oil in these sealed trans many times both before & after issues began.
Our Craftsman we have I saved changing fluid to 20W-50 3 seasons ago remarkably pulls our big hills fine again.
We use old original Wheel Horse tractors but my wife broke both hips in a fall back in 2016 & can no longer climb on them nor clutch one well. My newest WH is a 1987 414-8 speed and my 1st one still runs/mows/tills pushes snow like new is a 1976 B100-8 speed. Believe me never pass a decent one Horse with a Kohler K series side shaft engine. These tractors were certainly built to outlast several owners. I've done very very little to mine over the decades, only covid made me wait on a part for the first time ever.
I've repaired mowers for yrs as a side job and learned an easy way to change oil here even if one of these hydros dont have the cap on top to access its oil aka: sealed trans. One can simply remove the fitting on the breather tube to change its oil if needed.
I've never removed a trans just to change oil on one yet. I swapped many dead trans out thats for sure.
But folks I just use a drill pump with a small stiff hose, like 3/8 or smaller? Never measured mine sorry? Its a stiff polypropylene hose not rubber as they bend too much trying to shove one deep inside?
Simply stick that hose down inside the top of the trans and **** the fluid out. Taa Daaa..lol
You wont get all the oil out, its more like 90% or so?
Then I just reverse my hoses to fill the trans back up and Im done. Drill pumps only flow in one direction so you can't just reverse your drill, swap hoses on pump or switch in/out around to fill trans is all.
I can do it all in well under 40min on most riders and in -20 min on mowers with battery under seat, remove bat/tray your right there. Zero's are even easier.
The small amount of old fluid left inside wont matter as the new oil will easily mix & replenish it anyway. Not enough to worry about.
But on one that slips really bad like the wifes Crapsman we got free I simply drain/fill them again in fall or next spring. I dont think it necessary but I still do it.
So far I saved at least 3 dead trans like this. My wifes Craftsman was pretty well shot I thought? Im shocked its still rolling on its own but amazed it pulls hills as it would completely stop moving on level ground after 20 minutes of mowing prior. We have over 2 acres to mow here and Ive mowed it all a few times without issues since oil changes.
We always split the property up so generally & I mow the half with big hills but I had times I used the Crapsman to mow it all while waiting on a D center hole deck pulley to arrive last summer. It mowed it all just fine and Im on the largest peak in our county!
You know your up high when a cell tower is your neighbor and 10mph winds feel like 30mph winds in town feels..lol
Briggs once made a drill pump with a small stiff poly hose to use on old self propelled mowers as their oil drain plugs are blocked by belt/shield on bottom. Ive not seen their kit in yrs though. That's what mine was but I replaced the original drill pump several times from wearing them out.
I use it on newer sealed car trans without dipsticks & truck rearends too btw.
Get a drill pump at home store & locate several feet of stiff polypropylene or polyethylene 1/4 to 3/8 hose & fittings/adaptor to connect them. Its all found at home stores.
My old drill pump setup has saved me so much time/hassle over the yrs Its a go to tool in my Garage.
Peace happy mowing!!