Jack up the rear and pull the hubs off the axles. You don't have to remove the wheels first, but it might make it easier. The hubs are held on with a snap ring. You may have sheared the key, and thus no drive from the axle to the wheel. I think the key is part of the hub, but it may be separate. Even if this happens on only one side, it will prevent the tractor from moving.

Doug: This might sound like a stretch, but bear with me. I have a Simplicity with the Tufftorq 71G tranny. Mine stopped like yours did, and it had me scratching my head. I eventually found part of a spring laying on the mower deck - one that I couldn't identify from parts manuals for the deck. Turns out it was a spring for the idler pulley assembly for the drive belt. Cost? Spring was a little over $6.50, but it resolved my problem. Check the tightness of the drive belt, and maybe look for a spring.

Good Luck!

Good points... and to add: check for stuck brake / linkage.

Thanks for the ideas.

engine_tech you are correct. It's a sheared key on one hub. Much easier and cheaper to repair than the transmission itself! That's either a soft key or one tough transmission.

Thanks a ton for helping with this problem.

Doug,

I have an extremely similar problem with a Scotts S2554 with the Tuff Torq K66 transmission. It just does not seem like the transmision is engaging. It is like the pin on the back of the tractor between the wheels was pulled out so you could move it easily. When disassembling, I did find that the spline that attaches the tire/wheel to the axle was broken at the weld and the wheel could turn freely. I can replace that or get it welded. But I still can turn the input pulley freely and there is not out put to the axles. I have got my transmission torn apart and so far have not found anything other than the tranmission filter(s) on the inside could stand to be changed. Were you able to resolve your problem? Thanks!

Are you turning the input by hand? Expecting to get "turn for turn" output? This is a hydrostatic drive (fluid drive) transmission. You probably can't develop enough flow volumn to move anything on the output end of the works turning it by hand. At hand speed you are likely just "shearing oil".

Gravygoat: My Simplicity has the TT 71G. When I had it out to do a complete servicing, I tried to turn the input shaft by hand. It was very difficult even without fluid in it. Check to see if the pulley for the input shaft isn't stripped. The pulleys are made of softer metal than the input shaft, and sometimes the splines on the input pulley will shear leaving you with not much of anything. Pulleys are about $25.00.

"Thanks for the ideas.

engine_tech you are correct. It's a sheared key on one hub. Much easier and cheaper to repair than the transmission itself! That's either a soft key or one tough transmission.

Thanks a ton for helping with this problem."

I'll second that "One tough transmission"

While taking a break from mowing, I notice a hole in the pan, took transaxle off and then took pan off and all looked fine. Had hole helic arc welded and put back together, took a ride and all was fine stopped mower and had another hole at the same place. Hole was about where the expansion tank is only on the bottom. Help

I am also having K66 problems. My tractor stops on an incline and I needed to find a smaller incline to get back to my garage. Tractor speed has greater decreased lately. I replaced all the belts which didn't help. I have removed the transaxle and it cover. The gears look good and the magnets have minimal powdered coatings. With no metal filings and the gears looking in good condition. I believe the need to replace the cylinder block kits. Does this make sense? The repair kit is over $400. The tractor is 7 years old with less than 500 hours.
I replaced parts. tractor now runs like new. People at ToughTorq were very helpful.

This post was edited by beanbeanbean2000 on Fri, Jul 4, 14 at 22:04

would go thru the tuff torque troubleshooting c/l first..mebbe a fresh change of fluid might do..?

Here is a link that might be useful: c/l

I talked to Tuff Torq this afternoon. Their suggestion was what I was thinking. I did go over your trouble shooting info. As I do more research on the web it appears that my problem lies in the cylinder rebuild as Tuff Torq told me today. While expensive if the rebuild works it will save the cost of a new garden tractor. Thanks for your input. I did view a good U tube video on repairing a K46 which is very similar to the K66

My lawnmower just stopped suddenly as well.
The K66 seems to be broken / malfunctioning
When I turn one rear wheel, the other wheel turns in opposite direction!
Thanks a million for helping me with this problem

" When I turn one rear wheel, the other wheel turns in opposite direction! " That in itself is not an issue. It is called differential action. You will want to confirm that the belt is intact and turning the pulley on the transaxle for starters.

I've just found my problem is that the axle shaft key had failed. The axle but not wheel hub turns.

What hours are these k66 tranny's failing or showing signs of slowing? Is anytime after 500hrs barrowed time like most other TT trans? Thanks

My 18 year old Wheel Horse has a K61 trans-axle. I don't know the difference between K61 and K66. But my axle got sluggish at about 400 hours. I took it apart and found the "center block" was badly scored, allowing oil to bypass the pump and motor. I used carbide sandpaper and a flat block to grind out the scoring. Worked fine after that.

Last summer it was getting sluggish again. (800hrs) Rinse and repeat. This time I found TT had greatly improved the oil filter. My bet is this will improve life of the trans-axle. I also found the final drive pinion had worn such that the tips of the gear teeth had worn to about 50% of new. I got a new pinion (integral with it's shaft) for $120. I also replaced the ball bearing supporting the pinion end of the shaft. ($15) Refilled with Mobil 1 15-50.

Mowing season has started, and it is running great. tom

I own a few 30+ yr old original wheel horses with vert Kohlers, they have manual though. The original Vert horses with auto had Sundstrand trans that lasted forever, I never owned one.

My old neighbors has one about the age you have that's still moving but its only mowed 1/4 acre (all flat) at best. For yrs I thought MTD built hers but it actually wasn't.

I just noticed that I must have flunked math: my Wheel Horse is 28 years old, not 18. tom

lol.. Don't sweat it Geezer88, today's kids would all flunk doing math like we had back in our day. They've used calculators & pc's to do all their math for yrs so we'll look at it like your young all over again if your forced to use one. You may even fit right in with the "in" crowd..lol