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Tuff Torq K46/T40 to K66 upgrade

37K views 25 replies 9 participants last post by  Frogmore 
#1 ·
I'm curious about something on the K66 upgrade if anyone here has done it...

I've read through the manual for the John Deere L/LA/D-Series models from rjrtractor, and I'm curious what parts from the old setup would be used, specifically, the brake/accelerator/reverse rods to the transmission, drive belt, or trans pulley/fan. From what I read, it seems like one of the only unique things is the custom support brackets where the transmission bolts to the frame. I own a D140 from 2012 and I had an issue a few years ago where my trans support brackets came loose/broke and the trans was leaning forward and slightly tearing the frame where they bolt to the frame. A local welder had fixed some of those before and he welds angle iron to that area and makes it as thick as an X500 series. So, I'm curious if I would even need those custom brackets since mine has already been reinforced...

I personally removed my T40 trans after 100 hours and drained all the oil out and replaced with the 5w50. Luckily didn't have any metal shavings inside or anything, but I did it after reading horror stories of those transmissions failing very quickly. I'm still using it, but was curious about the k66 upgrade in case I ever do need to swap it out.
 
#2 ·
You did very well to change the oil in your transmission. I think the current price of K66 kit is $1600.
If you mow relatively flat lawn, don't pull heavy loads, and keep the cooling fins on the transmission clean, your transmission should last a long time.
 
#3 ·
I found some new K66's for under $500 shipped online. That's where I'm trying to figure out where the difference is between buying the transmission myself and swapping vs. the "upgrade kit" sold elsewhere at nearly $2k...

If the "upgrade kit" has a ton of custom stuff added, then I can understand, but if it's simply a different sized belt, or an extra bolt/washer/spacer here and there, I can't fathom spending the $ on that.

My yard is very flat, almost an acre. I do have small city ditches to mow (10" culvert pipes fit in these ditches for size reference). Most I've pulled is a weighted aerator or lawn sweeper. I'd eventually like to do some snow removal attachments down the road. I just got done putting on a new drive belt and tensioner pulleys, new steering sector and pinion gear, new wheel spindles (swapped the wheel bushings for the wheel bearings upgrade and installed the "poor man's power steering" thrust bearing sandwiched between 2 washers where the axle sits on the wheel spindle), and lubricated everything up real good. Next job is servicing the deck spindles and replacing the blades. I'm having that common issue with one of the deck idler pulleys being stuck because the bracket it slides onto must have come loose and the whole thing turns when trying to remove the nut. I may have to get my welder guy to see if he can get under that bracket and weld it in there so I can remove it. I don't think my impact gun will do it, but I'm going to try. Also my deck has lost a lot of paint so I may be having the whole thing blasted and powder coated too.
 
#5 ·
If I recall correctly, you can go up to a K58 without issue. The trick is knowing what sub model to get. Check out tufftorq.com for contact info. They may be able to provide you with appropriate guidance. Used to be that with the right parts from Tuff Torq you could easily upgrade a T40/K46 to K57.

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#7 ·
Be aware that even if you find a K66 at a reasonable price there are some additional parts that increase the price significantly. The K66 has 1" axles compared to the 3/4" ones on the K46. That means at least new wheels and tires and probably hubs. Used parts are sometimes available, but rarely cheap. New parts are expensive but readily available.

If your transaxle died with only 172 hours, you either got unlucky with a defective one or REALLY need a more capable tractor. What are you doing with it?

You can still get a reasonable priced K57 from Surplus Center. It is probably in the reverse direction of what you need, so you would have to figure out something about that.

I don't see any reasonably priced K66 transaxles right now, but they do show up every once in a while.
 
#11 ·
If it is still working and you have an appropriate property and tasks for it, keep using it. When it starts to fail figure out what you want to do differently next time. Or, if you already know it is not enough buy something better, just make sure it really is better.

I bought my first new car because it was cheap. I traded it in 3.5 years later because I was concerned it wouldn't last. Turns out the car I traded it in for was the one that didn't last. The third new car I got was finally one that I really liked and lasted for a decade before I traded it in, because my needs had changed.
 
#13 ·
How many hours are you guys getting from a 40J transaxle. My D140 is 9 years old now and I have 430 hours on it. I have change the fluid 4 times now, using Castrol 5w50 each time. Am looking at replacing it now. it is getting worn. I am not easy on it and use a pull behind tiller in the garden. For the cost of the rebuild kit a new unit just seems more cost effectve
.
 
#18 ·
Here is one way:

There are two other ways:
  1. Add a direction reversing lever in the control rod. There are some threads about that on one or more sites.
  2. Open the transaxle up and reverse the component that you are not supposed to reverse when you rebuild it (because it would go in reverse).

You should search for and read ALL. The many threads on many sites about K46 conversions/upgrades to make sure you want to take it on. There are some K62 transaxles available in the same price range you were looking at:

The K62 is better than the K46 and K57 and K58, but not as good as the K66 or K72 or K72. The K66 has 1" axles like the K58, so more things to buy.

The T40 is the only one that is a bolt on project. So you need to decide how much work you want to put into it.
 
#19 ·
Here is one way:

There are two other ways:
  1. Add a direction reversing lever in the control rod. There are some threads about that on one or more sites.
  2. Open the transaxle up and reverse the component that you are not supposed to reverse when you rebuild it (because it would go in reverse).

You should search for and read ALL. The many threads on many sites about K46 conversions/upgrades to make sure you want to take it on. There are some K62 transaxles available in the same price range you were looking at:

The K62 is better than the K46 and K57 and K58, but not as good as the K66 or K72 or K72. The K66 has 1" axles like the K58, so more things to buy.

The T40 is the only one that is a bolt on project. So you need to decide how much work you want to put into it.
Thanks for the info. Something to look at. The T40 only has problems now when I am using the pull behind tiller otherwise it's fine. At 400+ hrs I know it's only a matter of time. The K57 sounds good and it's cheaper. I just hate the thought of tearing into a new unit. Can't find much about swapping in a k62.
 
#20 ·
The K62 is similar to the K66. Any of the ones I listed is going to require some adaptation and the ones with 1" axles get expensive quickly because the parts are in high demand by people doing the swap. That was why I said read ALL the threads on the swaps people have done to make sure you know what you are singing up to do.
 
#21 ·
I emailed Tuff Torq just to see if they had an upgraded for the internals of the 40J. Nope but they did give me the link to the guy who cornered the market on all the K66 conversions. All I can say is somebody is smoking something, $2500 for the kit, it wasn't worth it when the kits were $1500. Looks like it might be a new 40J for me. Still need to check into the T57 some more.Thanks again for the links.
 
#22 ·
It is pretty simple, but that doesn't mean you have to like it.

It is about $1000 for a new T40 from Deere. It will bolt right up, assuming you get the right part for your machine.

A generic T40 is about $750 from other sellers. It might or might not be the same. It probably won't have the same part number.

You can get the Deere specific K46 or K57 or K58 for varying amounts of money. They will likely require some amount of adaptation to work.

You can get a different transaxle that will likely require some (maybe a lot of) work to adapt to your machine.

You can sell your machine while it is still running well and use the proceeds to get something better that is more in line with your needs.

You have a lot of choices, you probably just don't like them. That was where I was for about a decade. I then bought a new to me X534. I don't worry about the transaxle anymore.

You can wait around for the next round of surplus transaxles to become available. But, any of the ones that are really better will still be expensive and require you to buy additional parts that will make it more expensive. If you don't believe it is worth putting $1.5-2K into your current machine, don't do it. That was the answer that I kept coming back to. I don't believe new (even surplus) transaxles that are worth upgrading are ever going to get cheaper. Spending $700-1000 for a new T40 to put into a decade old 100 series machine will give you a machine worth about the cost of the transaxle to most anybody else.

So, sell the machine while it is still capable or use it till it no longer works. Keep changing the oil and be on the lookout for a junked mower with a good transaxle. I suspect they are somewhat rare, but do happen.

The $2500 kit is expensive and not worth it for a decade old 100 series, but it could make sense for someone that wanted an easy upgrade for a newer X300 series machine. I suspect there are actually a lot of people who have bought them. The kit does make it easy and gets you a bolt on kit with instructions that are very good. That is worth a lot to many people. Getting the dealer to replace the transaxle is probably $1500 or so, so $2500 for the kit that puts in a lot better one that most people can handle the install is not a bad deal. I didn't buy one, because I figured I could do it for less and don't really need the detailed instructions.

It sounds like maybe you don't need the instructions, but still want something that is easy.
 
#23 ·
Sounds like I am where you were. A newer "garden tractor" would be nice but just not in the works now. Just some background i'm a 30+ year GM dealer technician. I can do the work on it BUT i'm getting older and don't want the hassle of modifying yard equipment(ie. im getting old and lazy, lol) but I do enjoy my yard work and gardening so I have to have some equipment to play on. I have found new T40's around 650 shipped, that will probably be the route I go. I usually run vehicles, equipment until there is nothing left. I think the D140 still has some good life left in it. Priced the new S models, over 2500. Got sticker shock considering I paid 1900 in 2013 for this mower. Thanks again.
 
#24 ·
I think you are wasting money at $650 for a T40. It's not that you can get one cheaper. It is just that you will still have a decade old machine that is worth about what you put into it (assuming you don't pay yourself anything). Look at used machines that are better than what you have. What part of the country are you in?
 
#26 ·
Not much in your state, but here is a whole D130 for $650 (at a dealer)

You are familiar with mechanical things it sounds like. But the K57 (there are only two left last I looked). You should be able to do the install. You will probably need to take the transaxle apart. You might need to swap axles. You will likely need to flip the part that they earn you not to flip when doing a rebuild. While you have it apart add drain plugs and change the oil to synthetic. That will make it easier to change the oil next time. Change the oil at 50 hours and every 200 or so after. You will now have a solution that will last longer than the rest of the machine probably. It will take longer, but you will have a lot better result.

Or, just use the machine until the transaxle is really dead.
 
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