TuffTorq K46 Repair Guide with Pictures

[evo803]

LotsofGreenGrass,
I want to thank you for your post. My Husky 20K46 had issues last year and bought a drive belt and it seemed to work. This year it started acting up again and another new drive belt did not help at all.
I bought the parts you recommended from a local small engine repair shop for $225 and another $30 for oil and RTV.
I have to laugh at myself a little because I dropped the pan on the transmission before finding your instructions and all the pieces you warned us about fell out.
I put it all back together with the new parts. It took over 2 qts of oil so I had to get another one to top it off..
It seems to work great with one minor problem.
When I press the forward pedal, it goes backward - really fast!
When I press the reverse pedal, it goes forward
I swear I put all the parts in correct and there is no way to do it wrong and can't for the life of me think of what happenned.
I do not think so, but could I have put part#36 Motor Housing in upside down?
Happy and frustrated at the same time.
Thanks again for your help.

Take a look at post #19 of this thread , it looks like you installed this part backwards and will need to tear it down again to fix it.

 

[piratesignal]

The completed the K46 rebuild last Sunday, but wanted to share some additional findings I made along the way.

I think bench testing and purging the system is really a required step. When installing the new parts, it is easy to prime the pump that sits vertically, but the other one sits horizontally, and the oil tends to just drip out. When I bench tested mine, the oil level did drop just slightly, so I topped it off. If I had not bench tested, there would have been no opportunity to top it off.

I used Castrol 5w - 50 synthetic, cause thats what the parts store had. Also, Amsoil and Royal Purple were 15w - 50. I wanted to stay with the 5w - 50 weight.

Also The pulley shaft on my K46 has no nut, just a c-clip. Trying to figure out how to attach a drill to it was a challenge. It turns out that a 1/2" drive extention had just enough grip on the shft, and worked fine.

After re-installing the k46, I started the tractor and very slowly went forwards and reverse a couple feet at time. It hestitated for just a second the the first time going forwards, but then seemed to have full traction after that. I think bench testing really paid off here.

I kept going longer distances in forward and reverse and with greater speed. After a while I just went at it on hills, climbed into and out of a steep ditch. Full traction has been restored, and then some.

Below are some pics.

LotsofGreenGrass, you are the Man!!

 

[GeneralEclectic]

Also The pulley shaft on my K46 has no nut, just a c-clip. Trying to figure out how to attach a drill to it was a challenge.

Congrats on completing your project successfully!

An FYI about the oil: the synthetic you bought is, without a doubt, far better than the API:CD 10W-30 that was in there to begin with. Unfortunately new oil carries the API:SN designation that has LESS friction reducer in it (they're afraid of the long term effects of friction reducer evaporation and deposition on cats) than API:SM. I stocked up on Mobil1 SM for the cars when it was still available. (it was a lot cheaper then too) The Amsoil racing oil I mentioned previously doesn't have an API certification at all due to the very high quantities of friction reducers. Since it's used for off-road (i.e. non-cat) applications only, they can load it up with the good stuff. Also, the difference in viscosity between 5W and 15W in the low temperature range that we'd usually use our tractors is minimal. You might need to worry a little about it if you expected to do some snow plowing at -20F, but then, the K46 would be a rotten choice for that usage anyway. You'll find similar amounts of variation in viscosity between brands and subtypes within brands at typical tractor startup temperatures.

Since I haven't taken one of these apart for myself, maybe you can comment on this notion: would it be possible to install two general purpose nuts on the input shaft and tighten them against each other? (I don't know what the shaft looks like, obviously) Then you could use an ordinary socket on the top one with a hex drive adapter for the drill.

One more question: Was there some particular reason you chose to use the vent opening to fill the unit with oil? Isn't there a magnet under the usual fill hole that ought to be removed and cleaned? Did you do that?

 

[piratesignal]

One more question: Was there some particular reason you chose to use the vent opening to fill the unit with oil? Isn't there a magnet under the usual fill hole that ought to be removed and cleaned? Did you do that?

LOL! Good observation. The vent was leaking and badly cracked, so I decided to just use that to drain and fill. When I bought the parts, TT didn't mention getting a new fill cap, and I thought I might break this thing taking it out, and with there $25 minimum parts order I thought I might end-up in a jam. I cleaned the magnet with parts cleaner and a long nossle tube, and then an air compressor. That magnet had suprisingly little metal on it, but the other one was caked!

Next time I do this, or for anyone else doing this, you should order both the vent cap and fill cap along with the rebuild parts.

 

[buffy12590]

How about putting a magnet inside the large filter on the top which is round about 1.5" diameter as it appears in pictures. Wouldn't that do a better job than the small one already installed. Any reason why this isn't feasable?

 

[auraaura]

Help! I've just finished rebuilding my K46AC. It made a "pop" a few days ago and quit. Hadn't been losing power or anything. I found lotsofgreengrass's write up and decided to give rebuilding a try. When I took my tranny apart I found that the differential gears were trashed. Teeth sheared off and the transmission full of metal particles. I cleaned everything out, replaced the differential gears, put in the cylinder block motor and pump kits (per lotsofgreengrass's instructions) and a new filter. Filled it with 5W50, fired it up, and nothing. I've done the air bleeding procedure until I'm about crazy. I've gotten the tractor to run a "little". It will sometimes run but with a very loud groaning sound. Then it will stop completely. I can do the air bleeding thing again and it might run for a little while, then stop again. When I do get it to run it goes OK in forward, but when I try reverse it will go at only 1/2 pedal depression, if I push the pedal all the way down it stops. Weird...I'm at a loss as to what the problem might be. Anybody got any suggestions? I'd tear the thing apart again but don't know what to look for.

 

[desert1957]

First of all I would like to thank everyone on the Forum for their help.
I was very lucky , My (JD L120) K46 lasted 700+ hours before giving up the ghost.

During my overhaul everything you guys mentioned happened, LOL.

1.The little "Tic-Tac" pin fell out.
2.The Horseshoe clips fell out (differential)

Nothing broke internally but it needed a lot of parts I didn't think I would need and was glad I ordered. The pictures were a great help. I printed them out and out them. Stuck in a laminated folder and were used quite often during the whole overhaul process.

Pump, Motor, Filter, Fill cap, Vent Plug, Per 1 forum member's recommendations I ordered the "Spider Gear" set for the Differential, After a thorough cleaning of all parts I found the gears so worn they actually had sharp edges and were horrendously pitted from trash in the oil.

My overhaul took what seemed like a long time to bleed after start up, I had the usual OMG feeling of what did I do wrong or leave out. But eventually everything is back to normal or should I say SUPER normal.

Still has a very very small whine, but with triple the power and torque I'LL take it!

So let me say to anyone who thinks they can't do it , You Can.

Thanks again,
Desert

 

[desert1957]

Help! I've just finished rebuilding my K46AC. It made a "pop" a few days ago and quit. Hadn't been losing power or anything. I found lotsofgreengrass's write up and decided to give rebuilding a try. When I took my tranny apart I found that the differential gears were trashed. Teeth sheared off and the transmission full of metal particles. I cleaned everything out, replaced the differential gears, put in the cylinder block motor and pump kits (per lotsofgreengrass's instructions) and a new filter. Filled it with 5W50, fired it up, and nothing. I've done the air bleeding procedure until I'm about crazy. I've gotten the tractor to run a "little". It will sometimes run but with a very loud groaning sound. Then it will stop completely. I can do the air bleeding thing again and it might run for a little while, then stop again. When I do get it to run it goes OK in forward, but when I try reverse it will go at only 1/2 pedal depression, if I push the pedal all the way down it stops. Weird...I'm at a loss as to what the problem might be. Anybody got any suggestions? I'd tear the thing apart again but don't know what to look for.

Sounds like the little pin issue that likes to fall out, Its critical for pedal operation.

 

[auraaura]

I pulled the transmission back out of the mower and tore it back apart again. The bearing that goes under the cylinder block pump had literally exploded. When I drained the oil out of the transmission ball bearings were falling into the drain bucket. What the **** happened I have no clue. Anyway I ordered the thrust bearing upgrade kit (which appears to have all the damaged parts I'll need) and I'm going to try again. Everything is all cleaned up again and I'm waiting on parts. Thanks for the help, I'll let you guys know how it goes.

 

[abeal]

It's been a while so I thought I'd bring this post back up. I have a L120 that I need to do the rebuild on. My question is, what's the deal with the center case? TT says it should be replaced. I see that they have little filters now instead of the BB's. Can you get just the little filters and springs? I haven't taken mine apart yet...just trying to put a parts list together. Any help is much appreciated. Thanks