TuffTorq K46 Repair Guide with Pictures

[P901]

Hello, I went with the Permatex Black being that this
particular sealant has the highest oil resistance.

The shims were actually formed from stainless steel fender washers from our fastener stock.
Good alloy and plenty hard enough for the input rotational speeds/torque and horsepower.
(For custom transmissions we will use Air Hardened steel stock, surface grind to size and then heat treated)
For a lawnmower at 5.1mph top speed I think we will be OK with the stainless steel

The washers were too thick for each particular position but after boring out the center holes
to the appropriate shaft sizes so that they would fit nicely on the shafts then I knocked down
the thickness on the belt sander until I got into the "ballpark" with a fit that would have been too tight.
Once I had my "zero" clearance thickness dimension then the washers went to the surface grinder to remove just enough metal
to give .020" clearance for each position and of course to establish a precision parallelism of the washer mating surfaces.
So to answer your question regarding the thickness we will find that the thickness dimension will be different
for each transmission housing/gearset cluster relationship but in this case the shims ended up being in the .025" (Outer Intermediate shaft shim) to .045"
(Differential shim and Intermediate Gear Inboard shim) range.
The two factory standard "horseshoe" shaped differential pinion gear shims were also put up onto the surface grinder for a "cleanup" pass and to establish
the parallelism with the large fabricated stainless steel differential pinion shim sized to take up all of the accumulated dimensions to produce the final
.020" clearance.

Hope this helps, andrew

 

[P901]

Yes Dapped,

I though the same thing until I closely studied the internal bosses of the gearcase and realized that the pressure would
have been applied in one axis.
I will say that I was in the mindset to do a cleaning/flushing and oil change when I approached this project and then received
a bit of a shock when I saw the condition of the fitting of the gearset.
Fortunately the machinist was still at the shop at the late hour of the day and agreed to stay an extra hour to help me fabricate the shims!
So what was initially planned to be ~2hr project turned into ~4hrs, all in all not too bad.
Overall though, fortunately for the owners of these models the transmission is rather easily removed and installed.
Cheers, a

 

[Dapped]

P901
That certainly is a very good report you did and you could be on the right track here as to why all the failures. My oil was also full of metallic particles. and both magnets were plugged solid with shavings..It was my left (driver side)spider that ground off to the point of no contact, thus no forward or reverse. I put new gears in $44.00 from Tuff Torq but another $54.00 to ship FedEx here into Canada (no other choice for shipping). It seems to be OK and the trans-axle feels strong even in the heat of the day. Perhaps I caught it in time......hopefully, If it happens again I will definitely do the shimming, it make total sense..

Thanks
Don

 

[Voyager6]

I just did a K46 to K58 upgrade in a X304. I bought a new K58A off ebay and had to open it up and change the axles to the short stubby splined versions needed by the X304/X324, effectively turning it into a K58B (I did the oil drain plug modification as well). I too, was concerned on the axle play and how loose it was to the differential spider gears. I didn't measure it, but I bet I had at least 0.035 inches of play on each axle. Finally, I replaced the magnets with 1 inch by 1/8 inch round rare earth magnets with 14 lbs pull to catch more and smaller metal particles. These were at least 4 times stronger than the factory ceramic magnets (Note rare earth magnets can start to lose magnetism over 180F, but with 5W50 oil it should be fine). I recommend replacing them in any K46 rebuild, especially if you have the extra two magnets near the filter.

 

[Voyager6]

It doesn't help that most K46s have powdered metal gears. They probably tend to flake with any friction. Some K46s and all K58s have heat treated steel gears and they are likely to last a lot longer and shed less. If you do have wear on gears, I'd call Tuff Torq and ask them for the steel parts rather than put new powdered metal parts back in.

 

[P901]

Would anyone have any closeup photos of the wear on the sintered fusion gears (powder), and the steel gears?
Looking at the gears in the photos of my transmission I would say that these are the steel gears.
My experience with the sintered gears if memory serves are that the sintered gears have an overall dull grey appearance with
the shiny polished faces of the gear teeth being created after the case hardening and then finish grinding.
a

 

[P901]

Good day Voyager6,

Would you have a link to a site to procure the higher power magnets?

Thank you, andrew

 

[Djeff]

I experienced problems with my transmission(K46) and no luck in getting any help from John Deere. They said the transmission was not serviceable and had to be replaced at a cost of $600.00 +. My son and I pulled out the transmission and we are now waiting for our replacement parts to arrive. Looks to be an easy fix,but I will never buy another John Deere product. They claim they have no problems with their transmissions, but all you have to do is an Internet search and there are all kind of posts with the same issues. Even talk of a class action lawsuit.

 

[P901]

How many hours of use did you have?

What type of duty did the machine perform?

Have you drained the oil, if so, what does it look like ?

 

[pooleo]

Glad I found this info. Great. Last summer I drained the old oil and refilled with 5-50 mobil 1. The tractor performed as new. It would even pull the front tires off the ground if you held the brake, forward and let off the brake!

Tractor sat all winter. Pulled it out a few weeks ago. Was going ok, a little slower than I had remembered. After a cut lasting about an hr I lost reverse. It than started a massive grinding sound. Now at full forward it goes...well, lurches forward then stops. No reverse.

I am heading out to pull the trans out. I am going to look at the center case and try the home-brew milling job. Im sure its scrapped up good.

Will report back with pictures and info. If it works!

Oh yeah, I have an L120. 485 hrs.