TuffTorq K46 Repair Guide with Pictures

[GeneralEclectic]

I am a little concerned about the 'purging' process I read here. I don't quite understand the directions. But, I'll figure it out. Some people said they didn't need to do this.

You will do yourself a huge favor by downloading and studying the K61 repair manual. I posted the link to it a couple of pages back. Among a wealth of other relevant information on rebuilding this thing, it describes the purging process very clearly. You should pay particular attention to the description of procedures and techniques for motor and pump reassembly. Torque specs and tightening order are useful too.

Purging ought to be easy to accomplish on the bench, using a drill to turn the input shaft. That way you can top off the oil level easily if it's necessary. If there's a lot of trapped air that you purge when it's installed in the tractor, adding oil is much more difficult.

 

[piratesignal]

HEADS UP, GUYS


If you have a candidate K46 for repair, think twice about it. You can buy a BRAND NEW K46CR (the one with the auto-locking differential) for $436 at Sears Parts. Here's the link:

http://www.searspartsdirect.com/partsdirect/part-number/426121/0071/917

But WAIT! If you call right now (and you know we can't do this all day), you can apply a 10% off coupon code to any Sears Parts order!! Folks, this is a Really Good Deal. For $392 (plus ~$15 shipping and whatever tax you have) YOU GET A BRAND NEW COMPLETE TRANSAXLE WITH AUTO-LOCKING DIFF. The Hilliard differential alone is $252!

Note that the description of the part is a little sketchy, but if you Google the part numbers, you'll see what it is. Don't take my word for it, try it for yourself.

The coupon code is: Px11xSPNGEMAILLG

I tried it. It works. It expires 30 Aug.

While you're there, I suggest that you check out the prices for supplies like blades and oil filters. I found my Kawasaki OEM oil filters for $2.39 ea. You can't beat that with a stick.

Ok, now I'm feeling a little sick. I probably would have purchased the new auto-locker for $392. Thats only $100 more than I spent on the parts to fix my non-locker. I should have read a little deeper into these posts. I wonder if Tuff Torq takes returns?

When I drained the oil from my K46, I back-lit with an LED light, and there was a significant amount of metal shining. Not the worst I've seen, but not the best either.

Shoot! Now I don't know what to do!

 

[piratesignal]

You will do yourself a huge favor by downloading and studying the K61 repair manual. I posted the link to it a couple of pages back. Among a wealth of other relevant information on rebuilding this thing, it describes the purging process very clearly. You should pay particular attention to the description of procedures and techniques for motor and pump reassembly. Torque specs and tightening order are useful too.

Purging ought to be easy to accomplish on the bench, using a drill to turn the input shaft. That way you can top off the oil level easily if it's necessary. If there's a lot of trapped air that you purge when it's installed in the tractor, adding oil is much more difficult.

Thx GenElec! I saw your post and downloaded the K61 pdf. Good stuff. Thx!

 

[GeneralEclectic]

back-lit with an LED light, and there was a significant amount of metal shining.

Hmmm. That's interesting. It would be nice to know what metal that is, and how come it isn't stuck to the magnets. I don't know all what metals are in there, but for sure a variety of ferrous materials for the mechanics and aluminum for the case. You wouldn't expect a lot of aluminum floating around unless something very very bad, like a spun bearing, happened. Possibility for some brass or bronze I suppose. This, BTW, would explain the use of motor oil instead of the comparable 75W-90 gear oil that you'd sort of expect to find in there.

Do you still have the used oil? Any chance you'd be willing to send it into Blackstone for (~$25) analysis? That could potentially add a lot of new useful data to this thread.

If you want to feel even worse, look at the other non-locking K46s. I don't know what those variants are, exactly, but based on what you said above, you could have gotten a whole new one for about the same price as the repair parts.

 

[piratesignal]

Hmmm. That's interesting. It would be nice to know what metal that is, and how come it isn't stuck to the magnets. I don't know all what metals are in there, but for sure a variety of ferrous materials for the mechanics and aluminum for the case. You wouldn't expect a lot of aluminum floating around unless something very very bad, like a spun bearing, happened. Possibility for some brass or bronze I suppose. This, BTW, would explain the use of motor oil instead of the comparable 75W-90 gear oil that you'd sort of expect to find in there.

Do you still have the used oil? Any chance you'd be willing to send it into Blackstone for (~$25) analysis? That could potentially add a lot of new useful data to this thread.

If you want to feel even worse, look at the other non-locking K46s. I don't know what those variants are, exactly, but based on what you said above, you could have gotten a whole new one for about the same price as the repair parts.

I just went and looked at the oil again. I poured the oil through a screen/paper towel thing I made and it had moderate shavings. Looked about what I see in the boat motors I have done.

The rebuild parts arrived today. I am going to talk to Tuff Torq tomorrow about returning - box is untouched. If no go on that, I'll just continue with the rebuild.

I am re-tasking this tractor for snow-only. (44" blower, weights, tire chains), so the locker diff is something I am very interested in. The drive is 70' with about a three car area in front of the garage... no hills. Pretty simple, but lockers are nice.

I'll give an update on the parts return tomorrow. Otherwise, pics of the rebuild this weekend.

Thx Guys! Awesome Thread!

 

[piratesignal]

K46BE upgrade to K46CR (locking diff model) Update:

I just talked with Tuff Torq and they said that the CR model is only installed on tractors with 20" tires. I have 22" inch tires. They said the CR model will not 'fit' my tractor, and they wouldn't go into further detail.

I am trying to understand what tire size has to do with this??? Both models have 3/4" axle shafts and the casing depicted in the exploded diagrams appear to an exact match.

Tire size???

 

[piratesignal]

Update 2:

Talked to a pretty knowledgable guy at John Deere (pre-sales, at Corporate). He said the K46CR will fit, but the additional tire size will put more strain on the locking mechanism than it was designed for. 22" tires are only 10-percent larger than the 20", seems insignificant, but maybe he is right. The locker would be nice, but now I am thinking it may be just one more thing to fail, and I don't know the cost of those parts.

I told him I was putting on 80-pounds of Suitcase weights and tire chains, then he really started to not like the idea.

I am thinking I may just rebuild my BE model. I am not normally this indecisive... believe me!!

 

[GeneralEclectic]

Ehhh, I'm not so sure these opinions are well grounded in physical principles. Cutting to the bottom line, a given torque at the differential will yield 10% less drawbar force with 22" tires than it does with 20" tires. Where does all this "extra" torque come from that's supposedly going to destroy the differential? From the same motor and reduction gearset, that's where. IOW, the motor and gearset is going to deliver 123 lb-ft into the drive axle of a stalled vehicle whether the tires are 8" in diameter or 28" in diameter. Only the maximum drawbar force will vary with tire size. The capability of the transaxle to deliver torque is a function of the transaxle, not of the tire size. Tire size dictates merely the motive force v. output torque scale factor.

Now, you *could* look at this another way: For a given load on the vehicle (e.g. shoving a snowblower into a pile of snow), the larger tires will demand more torque from the transaxle for a given amount of push, thus the internal loads on the moving parts will be higher (everything else equal) and presumably wear will increase and lifetime will decrease. Of course, this is true for a continuum of tire sizes. The thing will last X hours with 22" tires, 1.2X hours with 20" tires, and 1.5X hours with 18" tires under the same use model.

If you put high quality synthetic oil in there and change it every 100 hours, there will be no problem with the larger tires, IMO. You have the added advantage of using the machine mainly in cold weather which will also have a favorable effect on oil breakdown and wear, though with a high quality synthetic, that will probably not amount to much. If you added an external oil circuit with filtering, it will probably last much longer even without the 100 hour oil changes.

My new K46CR now has 4.1 hours on it, with the factory 10W-30 API-CD mineral oil fill. As soon as the miserable hot/humid weather here lets up it's coming out for draining and refill with Amsoil 15W-50 synthetic racing oil. It's going to be interesting to see what, if any, metal is floating around in the oil with this little use on it.

 

[GeneralEclectic]

One thing: it's possible that the transaxles intended for 22" tires use a different gear ratio than those intended for 20" tires. Short of disassembling a variety of transaxles and counting gear teeth, I'm not aware of any way to determine this with any certainty. If this is true, then I'd have to agree that you're probably better off with the intended gear ratio. Also, the maximum rated output torque, which is widely quoted at 123 lb-ft (IIRC) would be proportionally different for 20" applications than for 22" applications.

It would be helpful, but not definitive, to see if the part numbers of the intermediate gear or the ring gear on the differential are different for transaxles intended for the two tire sizes. Maybe some of the readers here can post up their K46 variant along with the tire size so we can compare internal part numbers.

 

[piratesignal]

GenElec,

Appreciate the info and the contribution to this thread! I've decided to go forward with rebuilding my existing K46BE. I am still relatively new to tractors, and this definately won't be my last. I've learned alot about the tractor business and about what I would want in my next one. These things are Great Fun!

I run Amsoil in my other toys, and will add the 15w - 50 Synthetic when I do the re-build this weekend.

This whole K46 issue has been a great exploration, and I met some cool people along the way!

Congrats on the new machine, sounds really nice.

The Pics of the rebuild are coming this weekend! Yeah!!