My John Deere won't climb hills after it's been running for about 15 minutes. It happens slowly and eventually, it just stops climbing; a few years back, the hill wasn't a big problem but now I have to let it rest for 30 minutes and then finish mowing. My wife suggested I stop eating and that the extra weight was putting undue wear and tear on my riding lawn mower...

John Deere HydrostaticThe problem didn't start with the steep hills of the house I'm in now, it started with the previous yard which was a small, flat lawn less than half an acre. After about a year, I started to notice a loss in power; not enough to prevent mowing but enough that it was noticeable. Once I moved and started mowing the hills, it became progressively worse.

I have an extremely steep hill, so steep that I have to bend down when riding so that my center of gravity is lower. I realize that such an incline will wear down a tractor, but I have a John Deere and was under the impression that these riding mowers are the toughest in the business. (and I must add that this started before I started mowing that big hill and guessing that the big hill just made the defect stand out sooner than later!)

Note: Check out my tip for when your John Deere Mower Stalls if you are not having problems losing power.

I started reading the John Deere tractor forum and found a few suggestions on how to fix the problem.

Option #1, Replace Fluid on K46 - Worthless
One suggestion was removing hydrostatic transmission and replacing the fluid. This is not an easy task and some users claim that by the time the fluid is bad, the transmission may be shot - yet others claim that they have seen a major improvement in performance after the change.

From what I understand, there is no way to replace the transmission fluid in a John Deere L120 (applies to L130 and a few others) without first removing the transmission - not an easy task!

Option #2, Have John Deere repair my transaxle - Same Problem!The second option is to bring it in and have it repaired; however, when I called my local dealer, he stated that they just chuck the old transmission and stick in a replacement. He said that he can not install the transmission of another rider and that it has to be an exact replacement (original parts). The cost for that original hydrostatic transmission is $669.33 ($100 labor included), unfortunately, I would end up with the same problem over time.

Option #3, Buy a better model John Deere - Not Fair!
The third option is to buy the closest model riding mower that has the ability to change fluid and filter. That model is the John Deere X360 and runs $4,895. Not only is that too much, but my bagging attachments and snow plow from the L120 will not fit the X360, so I'm looking at another $2,000 bringing the total to almost $7,000!

Option #4, Install a K66 Transaxle upgrade kit - Worked like a charm, wow!
The fourth option in dealing with my John Deere that won't climb hills is to buy a transmission upgrade kit and I am NOT mechanically inclined! This is the option I ran with and I'll explain that in detail shortly. The kit costs almost $1,000 and greatly increases the power of your lawn mower giving you the same ability to change fluid as does the X360.

UPDATE! Skip the Upgrade Kit (now about $1,800) and buy a Husqvarna GT

You can read the rest of this page which I wrote when the upgrade kit was in the $800 range, which made sense, but for the price it costs now (around $1,800) and the fact you'll be putting the new transmission on an old machine, makes buying a new (or used) Husqvarna GT the better option. Here are some models to choose from right now, with free shipping - and eBay guarantees the purchase!. Most GT Models will have the K66 transaxle, such as the GT54LS, GT48XLSi and the GT52XLSi. If in doubt, just ask to make sure it's has the K66.

K66 Transaxle Upgrade Kit Cost (Now $1,800)

I did a lot of research and there are manuals you can buy to do it yourself; you'll save some money buying the transmission separately, but you have to run around and get all the parts. For me, spending $700 for a transmission that will break down again or $300 more ($1,000) for a transmission that will turn my L120 into a beast was a no-brainer.

The upgrade kit I purchased comes with a brand new Tuff Torq K66 Hydrostatic transmission, bigger back wheels (which you need), all the parts and a very easy to understand color manual. I mention transmission a lot, but technically, it's a K66 Transaxle Upgrade kit.

It took two of us 5 hours (seemed like half that) to remove and install the new Hydrostatic transmission and what a feeling of accomplishment! The John Deere transmission upgrade kit and the documentation was one of the most complete and easy to understand I've ever read - the pictures basically walked us through the entire project step by step.

I was, and still am, blown away by the power of my upgraded L120! It actually brings the front end quite a ways up when starting off at full speed :) As for the hills, no problem at all and in fact, I can stop in the middle of the hill and continue without any problems. No more groaning sounds like the old transmission made (perhaps it is my imagination, but now I hear it growl).

I have a new love for my John Deere and knowing that I have a tricked out tractor makes it all that better. As for winter, no problem - I'm confident that the bigger tires (big knobbies) and super powered Tuff Torq K66 Transaxle will not only handle the worst of snow, but provide hours of entertainment as well :)

I did a lot of research and found a John Deere transmission upgrade kit. I could see from forum posts and eBay status that it was safe not to mention that eBay guaranteed the purchase; the fact that I had a phone number to call made me feel that much better.

I can tell you that Roger is serious about his customer service. Not only did he keep in constant communication, but I had tracking numbers, status updates and tips from other owners that he passed along to make things easier. I called him a few times to ask questions and each time, he was there for me. Who does that?!

I want to let you know that I have never met Roger (who sells the kit) and never communicated with him before I made my purchase. I took a chance buying this kit and was thrilled to have a smooth purchase and above the bar support! I did this review because in a world where integrity is so hard to find, it was nice to deal with someone that stuck by his word!

At the time I purchased the upgrade kit (years ago now), the cost was fairly cheap and here is what I paid:

John Deere Transmission Upgrade Kit L130, L120 & others
$879.00 Upgrade Kit *
$99 Shipping *
*see note below as to price changes

You would have received:

Tuff Torq K66 hydrostatic transmission / transaxle that will replace your weak or worn-out K46 with a K66 which applies to John Deere L130, L120 & others

This is a Do-It-Yourself kit and provides all the parts that you will need, including the required larger wheels. For a person with average skills, about five hours is required.

K66 Transaxle Upgrade Kit Included:

  • A brand new Tuff Torq K66 Hydrostatic transmission.
  • A new set of 23" x 10.50" - 12" wheels and new U. S. Made Carlisle "Turf Tamer" tires. (Pictured in listing)
  • All the required various Genuine John Deere transaxle installation parts. All the parts, even the nuts and bolts are neatly bagged and identified.
  • A 28-page detailed, pictorial, installation manual that anyone can follow. (See photos for view of the Index and a sample page.)
  • Free technical telephone or email support to help you out if you have an unexpected problem, email Roger.

Additional things you will need:

  • Two auto-type jack stands.
  • Basic hand tools and a basic set of metric box end wrenches and a 5/8" US box end wrench.
  • A safe place to work.
  • A "Helper-Outer." (i.e., friend or spouse)

I got lucky finding this kit and excited that everything worked out as promised and service was as good as promised making my John Deere transmission upgrade easy.

Note: Since I originally posted this review, demand for the K66 transaxles increased such that the surplus of 500 have been depleted. Although arrangements were made with Tuff Torq to make new K66's for Roger's kits, the low cost I received is no longer available and the new price is such that for a little more, you can buy a new tractor, something other than a Deere! John Deere has also raised some of their prices, so

the kit I bought for $978 is now about $1,618!

8/19/2014 UPDATE: CLASS ACTION LAWSUIT, SIGN THE PETITION.
It's obvious from the number of comments and page visits that this is a very serious problem, so I'm collecting names to start a class action lawsuit for those of us that own a John Deere "L' series Lawn Tractor. To date, we have around 1,400 visitors from around the United States that have added their name to the lawsuit. We are working on finding a lawyer to handle the lawsuit and will update as we have more information. Once I have the attorney, I will likely close this form, so get your name on the list if you feel you've been mislead / ripped off / sold a lemon.

The fact is, John Deere installed a completely "non-serviceable" transmission in their "L" series Lawn Tractors, know that their transmission will break down under normal conditions, and worse, charge you $1,800 for the K66.

If your L-Series experiences one of the following, please express your interest in being compensated:

  • Tractor slows down and/or has power lose while going up a hill.
  • Tractor moves very slow or not at all in reverse.
  • A loud whining noise can be heard from the back of the tractor when in use.
  • Your tractor does not have a method for checking or changing the fluid level of the hydrostatic transmission.

2/11/2015 Update: The John Deere transmission upgrade kit is sold on eBay and now $1,798. If I were you, I'd check out the product on eBay and ask Roger to explain why it has increased in value and what you could buy for that amount. I'm not sure if it's the entire tractor that's been upgraded, or the transmission, but I can tell you this... That k66 transaxle is still kicking butt and no change in performance! I've got the steepest hills around (I'm going to video take myself going up and down the hill so you can see for yourself) and the monster tires I received with my kit make snow plowing a snap!

The fact that Roger has a good number of eBay reviews since I purchase my kit years ago and 100% positive feedback over the last year is a sign he's still living up to his word and on top of that, eBay backs up the purchase.

I need to point out one last thing! What John Deere put out on the market, and what I ended up buying, was completely wrong! I trusted that name, regardless of the price. I figured I'd get the same product farmers get, not some poorly made version that required me to make it right! So, I've put together a class action lawsuit form and collecting names - if you're in the same boat as me, take a minute and sign the form.