Sundstrand hydrostatic transmission

Sundstrand hydrostatic transmission

Cub Cadet, Simplicity, Alles Chalmers, Ariens, and John Deere have garden tractor models that have hydrostatic transmissions. If you have problems with a hydrostatic transmission normally you have to make a decision to:

a: Rebuild it. (somewhat expensive and can be done only if the parts can be found)
b: Replace it. (very expensive and only if the same or compatible transmission can be found) or
c: Get a different garden tractor.

Obviously it’s best if you prevent problems with the hydro transmission before they happen. One of the most common and preventable causes of the hydrostatic transmission failing is pulling/towing the garden tractor. Just don’t do it, not even a short distance. If we need to move a non-running garden tractor around the shop we will even skid the wheels rather than take the chance of ruining a good transmission. We specifically overhaul Sundstrand hydrostatic transmissions, there are other brands. These are a couple of e-mailed questions we have answered about Sundstrand hydrostatic transmissions. It will give you an idea of the symptoms of the hydrostatic transmission failing and a few things to check out before you overhaul or replace it.

Q: I have a question concerning a larger piece of equipment. I have an older Ford front loader with the Sundstrand hydrostatic drive. About a month ago while moving a load of horse manure the unit decided to not move anymore. I called a friend and he guessed that it could be the neutral switch just out of adjustment. Ring any bells for you guys? I don’t know anything about hydrostatic transmissions and am lost!

A: A few recommendations:

1. Check if the driveshaft isn’t stripped and slipping on the transmission.

2. Check the linkage going from your hand or foot control down to the transmission and make sure it did not unhook or fall off.

3. Also check on the arm that hooks on the shaft going into the transmission and make sure it is not slipping.

4. If you have a gear transmission behind your hydro transmission, make sure that it did not jump into neutral.

5. Then, did you check and see if you have a broken axle?

Q: I have a John Deere LX 176 lawn tractor, 38 inch mower deck, with a hydrostatic transmission. It has a few hours on it but is in good condition, with one small exception. It has slowly refused to climb the slope in my front yard. About half way up it simply gives up and makes a shuddering sound. This seems to also be aggravated by temperature. The colder it is the better it works and then as the tractor gets hotter it won’t back up even on a slight incline. I fear the hydro needs rebuilding, do you agree?

A: First check to see if your traction drive belt is not slipping or you have a locked up idler pulley.

Q: I checked both conditions as you suggested and both are to specification. It has a new John Deere belt. The condition as I described it before also gets worse as the temperature of the transmission rises. After an hour of use the speed in both forward and reverse slows with any change in grade. I have had several John Deere riding lawn mowers before and used them on the terrain with no similar results.

A: Yes, I agree, you are correct that your problem is a bad hydrostatic transmission. It looks as though there might be 3 different transmissions, so we need to start with getting the serial number from your lawn tractor. 1-800-618-8738

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2 Responses to “Hydrostatic-Transmission-Rebuild”

  1. I have a JD G100, I have changed the drive belt for the tranny thinking my problem was a worn belt for the hydrostatic. It did not. So when you try to go forward it surges a little and the same for reverse with no movement. New tranny or rebuild?

  2. Yes, you need a new transmission. I would just run it until it quits as it might still go a long ways.