TuffTorq K46 Repair Guide with Pictures

stackhsc · Apr 23, 2020

So I pulled the transmission apart after work. There was a fair bit of metal in there, not so much in the fluids but on the magnets. The one near the differential gear was the worst with the largest filing, the others had more of a powder /very very fine particulate.
The differential gears are , imo, pooched however I don稚 see any signs of wear on the pistons on the pump or motor. The filter on top is clean as a whistle and the mating surface on the washers is smooth, can稚 feel any thing noticeable with my fingernail on any of the mating surfaces. It was whining and losing some power so there must be something worn. I guess I致e got to figure out if I want to throw a new set of differential gears at it for 100 bucks or so and maybe a slightly thicker oil and give that a whirl or a rebuild kit plus gears at around 750. I知 thinking at that price I can probably find a full transmission though as I致e seen some new online sitting right around that mark.

Is there anywhere in particular I should check for wear that I might be missing that could be causing the lack in power?

I知 kind of leaning towards clean it up. Throw the 100 at it with a thicker oil and run it until it blows and get a new or retrofit at that time.

Thoughts?

stackhsc · Apr 25, 2020

Washed the whole thing down. No signs of evident wear on the pump cylinders/pistons, any of the mailing surfaces or anything other than the diff gears.
Is there a way to test the springs in the pump and motor? If they were weak would this cause the bypass issues when the oil is warm?

Kyle_in_Tex · Apr 25, 2020

stackhsc said:
Washed the whole thing down. No signs of evident wear on the pump cylinders/pistons, any of the mailing surfaces or anything other than the diff gears.
Is there a way to test the springs in the pump and motor? If they were weak would this cause the bypass issues when the oil is warm?

Many are precisely sanding the faces if they have a wear "scribe" circle at the contact area.

stackhsc · Apr 25, 2020

Kyle_in_Tex said:
Many are precisely sanding the faces if they have a wear "scribe" circle at the contact area.

Precisely sanding?

Kyle_in_Tex · Apr 25, 2020

stackhsc said:
Precisely sanding?

Tbunn said:
Kudos to LotsofGreenGrass and P901. Your info proved invaluable in fixing an ailing JD L130, 23HP Kohler, K46 transaxle. My neighbors JD had all the symptoms: slowing over time as you mowed, groaning, and in the end it struggled to move at all. At 406 hours I removed the rear end and dumped the oil. It showed all the signs of sever temp breakdown. I first tried just a fluid change, but was not satisfied with the results and decided to open up the trans. Bottom line: I used a plate of thick glass as a backer and sanded the mating surfaces of the Cylinder block (pump) and the Cylinder block (Motor) as shown to remove the wear rings. Started with 320 and finished with 600, both grits bathed in oil. Cleaned up everything put it back together as shown and we were off to the races. No groans and much more power to the wheels. Thanks very much for your time to document what you found. PS: I also shimmed the same areas as P901 did. It tightened up the drive train nicely. Thanks for the tip.

Tbunn explained it well.

stackhsc · Apr 26, 2020

I値l check it out. Are they sanding the surface on the motor and pump and/or the surface of the block they mate too?

stackhsc · May 12, 2020

I replaced the differential gears tonight and sanded the mating surfaces with wet sand paper 600 followed with 1000. End result they looked very shiny and smooth.
There seemed to be what I considered a lot of slop in the gears. I don稚 remember it being there when I took it apart. I looked at the schematics and there doesn稚 seem to be anything missing. Basically the axle through the little block, into the diff gear, a circular clip over the axle and the the hoses he shaped clip beside that on both sides. Seems to still be a lot of play. Is that normal or are they normally pretty tight.

radios1 · May 12, 2020

stackhsc said:
I replaced the differential gears tonight and sanded the mating surfaces with wet sand paper 600 followed with 1000. End result they looked very shiny and smooth.
There seemed to be what I considered a lot of slop in the gears. I donç¨š remember it being there when I took it apart. I looked at the schematics and there doesnç¨š seem to be anything missing. Basically the axle through the little block, into the diff gear, a circular clip over the axle and the the hoses he shaped clip beside that on both sides. Seems to still be a lot of play. Is that normal or are they normally pretty tight.

slop will make the gears bang when engaged, not good. there must be spacers of varying thicknesses that can be used to minimize the slop, just like on a car/truck differential..