This is a good review of some of the units used by JD:

 

This is great!
I was wondering what the load limits were for tractors and this answers my questions.
Looks like a quick indicator for a good tractor used to push snow or pull a heavy trailer would be a transaxle that has the flange style axle.
I know I have been overloading my LT155 by occasionally pulling a trailer and I am looking for a replacement.

 

I know the K91 used in the 4x5 and the K92 used in the x7xx series are quite reliable. The early K91 did have a design flaw using only two gears in the differential spider gear assembly and this was corrected with a four gear set after I broke the gears in my 1994 JD445. No issues since.

 

What is your objective? Is this just general knowledge research or are you trying to decide on a lawn tractor to buy based on transaxle quality/durability?

Sent from my SM-A426U using Tapatalk

 

What is your objective? Is this just general knowledge research or are you trying to decide on a lawn tractor to buy based on transaxle quality/durability?

Sent from my SM-A426U using Tapatalk

I am just looking for general knowledge. I may be in the market for another tractor and was wondering what the differences between all the different transaxles. I am also interested in any issues that certain models may of had.

 

I would say they are all equally durable and reliable when used for their intended purpose, maintained, and not abused.

A lot of people love to hate on the K46 because it fails from being used beyond it's intended purpose. The K46 is be far and above the most common turf torque you are going to see out there with a millions of them running strong for years. A lot of people are very vocal about them being weak because they don't handle hills or towing heavy things well.

To me that is like saying the Toyota Corolla is a piece of junk that fails all the time because you decided to tow your boat with it regularly, in San Francisco.

 

I would say they are all equally durable and reliable when used for their intended purpose, maintained, and not abused. A lot of people love to hate on the K46 because it fails from being used beyond it's intended purpose. The K46 is be far and above the most common turf torque you are going to see out there with a millions of them running strong for years. A lot of people are very vocal about them being weak because they don't handle hills or towing heavy things well. To me that is like saying the Toyota Corolla is a piece of junk that fails all the time because you decided to tow your boat with it regularly, in San Francisco.

There are different variations of the tuff torque k46 transmission it's not one K46 fits all..

 

Which one did my JD 285 have?

 

The 285, same as my 320 has a Sundstrand BDU-21 which is probably a little stronger than a Tuff Torq K72. Very good hydrostat.

 

I've had horrible luck with the lighweight non-serviceable ones. IMO a tractor shouldn't be sold that can't handle pulling a lawn and garden cart (especially because they put a tow point on all of the tractors).

That's why I got my 330: I blew up two box store tuff-torq transmissions doing extremely light work on my flat property. (Things like pruning bushes and using the lawn cart to take the clippings to the woods). That shouldn't stress the tractor, but it apparently did.

 

My dad ran riding mowers for about 45 years.

I don't believe he ever towed with one and I know he never pushed or blew snow with one.
Yes, we are in a snow area north of lake erie.


I guess I'm arguing that not everyone needs a hydro suitable for ground-engaging work.

 

I want to know because I might want to build one of these: (like I need another project)

 

I do not know what my JD GT235 has but its a 2000 model year and has been completely trouble free. I have some steep hills I mow every year and I pull a brinly roller full of sand every spring. I will sorely miss that tractor if anything catastrophic goes wrong

 

I have a 18 year old JD L130 with the K46. The hour meter quit at 300 a few years ago, so don't exactly know how many hours. It's never given me any problems, other than on real hot days and running the tractor for 1½ hours continuous, it wouldn't pull my steepest hill. When the transaxle was cool it had no problem pulling the same hill.
It is a lawn tractor, so I never really abused it. Maybe 200 - 250 lbs. max in the trailer or pulling 3" +/- limbs out of the woods.

Years ago, I did an easy modification on the L130 which made it pull better. I attached an extension onto the foot pedal, so it could be pushed further down, thus more pulling power. I believe this contributed to extending the life of the K46.

 

JR how does "pushing the pedal further down" give more pulling power? I'd think if anything that's give less?

 

Not positive but I would hypothesize that if the linkage doesn't allow full travel of the control valve, flow is limited. Oil flow = cooling. Think of it like loading an air cooled engine at low rpm. sill makes power but the fan's spinning slower blowing air through the fins reducing heat rejection. Most hydrostats don't have a strong cooling loop or heat exchanger.

 

The only thing pushing it down more could give is more speed -- and only if the linkage has been bent/misadjusted so it is not achieving full travel.
From threads on this site it seems that linkage issues are common. (Perhaps more so with the reverse direction)

 

Also have a GT235. Tractordata.com says it has the K71. In 20 years all it's needed is fluid changes and a belt.

We have hills, and machine has had cast wheel weights all around from day one. No fluid. When the hitch gets used it's usually because something's stuck.

 

Many of the machines over the years used a plastic reverse pedal which with age, would flex and result in failing to push the levers under neath their intended distance. It's easy enough to fix with either a new pedal or a modification to allow the pedal to be pushed as far as necessary.

Also, just FYI, on many of the machines, you can actually LIFT the forward direction pedal and it will back the machine up. I found this out when the reverse pedal on my 455 broke, which was a plastic pedal. Well, it didn't actually "break", it stretched.......so it didn't rotate the shaft on the linkage to back up the machine. Of course, I was pulled into a corner with the MC519 cart attached and full of lawn debris.

I stuck my toe of my boot under the forward pedal edge and lifted the forward pedal and "whal-la", the tractor backed up and FAST.......I didn't realize how much the stretching of the plastic in the reverse pedal had slowed the machine down until full reverse speed was returned with the repair.

I would DEFINITELY focus on a Tuff Torq with the flanged axles......they are designed for more garden tractor use while the other tend to be more riding mower use............

Also, the k91 has the oil cooler built into the lower portion of the 455 radiator............

 

I'd never consider one with a K46.

Just look at all the complaints and issues with them, don't cheap out, buy a better used machine if $$$ is a concern.

 

Some Tuff torq zt transaxles are made with powder metal gears (made by compressed aluminum magnesium powder) some have steel gears some have hardened steel. Powder metal gear is weak breaks easily JD used these a lot tzt7 type II has this tzt7 type III has options for steel however they seem to be trying to get rid of the steel gears in type III as well

 

An easy way to think of it is the bigger the number the stronger it is. T40 is the weakest followed by the K46 being the next weakest. K66 is where they start to get strong enough to do ground engaging work.

 

Hey I know I'm late but I'd like to pitch my opinion in in 2020 I bought an e120 it came with a tiff tourqe tl-200 up until 100 it worked just fine it still does but I swapped it with that trans I did some ground engaging work I pulled a 6 foot independent scraper a 3 foot independent that just cuts doesn't actually move dirt around and I did some rock crawling all with a stock tractor and I mean the only issues that were present were really traction I think these transaxles only make about 100ish foot pounds of torque but a couple months ago I bought a wrecked gt5000 for 60bucks the trans was really the only good part and all of the front steering I planned to make a go cart and I got to mount the trans and after that just left it engines are pretty expensive nowadays and I had been considering putting the gt's axle into my 120 and I did there are some things I still need to figure out like the tl-200's foot pedal automatically sets itself at zero no forward no reverse not the gt's and I also have to figure out cooling but that's about it the gt I had comes with a hydro gear 3000 series more than double the tourqe (260) and I think it surpasses the tuff tourqe k62 by like 20ft lbs or something but falls short of the k66 the only downside is I don't know how hard it's been abused so just in case I'm keeping the original e120 transmission with all the linkages and everything but I mean if u want a nice good transmission most of the peerless gear transmissions are pretty stout I mean if u want to tow or drive up steep hills unless you have a high end hydro I'd go for a gear drive if u can find an old craftsman for cheap they all mostly used gear drives

 

I would say the K92 is the best Tuff Torque hydro transaxle offered in John Deere garden tractors.

 

What JD Lawn Tractors come with the K92?

 

X7xx series mowers come with the K90 transaxle. X5xx have the K72. X3xx have the K58 and K46.

 

As someone mentioned JD should never have installed K46 on lawn tractors with large rear tires because it indicates that it can be used for heavy work. I have an L120 with 300hours and the transaxle is shot. Yes, I used it for pulling loads plus uphill. I feel now that it's all marketing to trick consumers to buying what looks like a heavy duty tractor when it's actually not. If they were serious about not using it for heavy load they should have put a big sign on the tractor and sales floor indicating so.