Toro LX425 Surging

TomS

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Hope someone can help me before I destroy the differential on my Toro LX 425 garden tractor. When going downhill the tractor will free wheel then the engine compression slows the tractor, then it does it again ad so on and so on. The problem is that the differential is absorbing the mass weight of the tractor and anything I'm towing. This started about a month ago. Not sure what's causing this but sooner or later something is going to break. Ay ideas?

Tom S
 
If the engine is surging on the governor it needs the carb cleaned out to get the main jet and idle jets working properly and it probably wouldn't hurt to check the exhaust to make sure it isn't carboned up too. That will definitely cause a throttle hunt which will pull and tug similar to what you are describing. Engine make and Model will definitely help with troubleshooting firther too.

Bob
 
If the engine is surging on the governor it needs the carb cleaned out to get the main jet and idle jets working properly and it probably wouldn't hurt to check the exhaust to make sure it isn't carboned up too. That will definitely cause a throttle hunt which will pull and tug similar to what you are describing. Engine make and Model will definitely help with troubleshooting firther too.

Bob

The motor is a Kohler Courage 20 HP. For clarification the motor isn't surging, it's the tractor. The tractor freewheels going downhill then the engine compression kicks in and slows down the tractor, then it freewheels again the slows. It does this whether the engine is running or not.

After writing this it came to me that this could be a differential problem. Could it be the differential is disengaging then re-engaging? It's got me stumped.
 
I removed the differential and disassembled it for inspection. I was expecting to find something broken but all the internal parts were in great shape. Took it to the local Toro dealer and they also inspected it. They said everything looked good to them too. Put everything back together and adjusted the shift linkage per the factory service manual and installed a new drive belt as suggested by the Toro dealer. Still have the same problem; rolls out of control down hill with intermittent or no hold back at all. Just a loud clicking/ratcheting noise like gears are trying to mesh. Makes no difference if the engine is running or not. I'm at my wits end. Any thoughts on what's going on.

Thanks
 
Is your engine hard to start at times? ......like it has a weak battery?
 
No problems with starting. Why do you ask?


Just weeding out possibles.

Be sure to replace both drive belts, too.

Here's just a shot in the dark, so to speak....
Check the idler pulleys on the drive belt (there's 2 of them), also check the tension springs on the drive belt idlers.

Also check all pulleys on the drive system for wear grooves.

Here's why I suggest this....We had a John Deere in the shop at the first of the Spring that would pull fine on flat ground but would not pull up hardly any grade. The customer had already taken it to another shop and they replaced the belt and changed the oil in the transaxle but it did not fix the problem. As my son was inspecting the tractor he found that all the pulleys on the drive system were slightly worn, he replaced the pulleys, put belt back on and it worked like a charm. The customer was and is tickled and has recommended my son to others for their repair needs.

Not saying that this is your problem but it is possible and should not be ruled out. :thinking:

Toro_lx425.jpg
 
Just weeding out possibles.

Be sure to replace both drive belts, too.

Here's just a shot in the dark, so to speak....
Check the idler pulleys on the drive belt (there's 2 of them), also check the tension springs on the drive belt idlers.

Also check all pulleys on the drive system for wear grooves.

Here's why I suggest this....We had a John Deere in the shop at the first of the Spring that would pull fine on flat ground but would not pull up hardly any grade. The customer had already taken it to another shop and they replaced the belt and changed the oil in the transaxle but it did not fix the problem. As my son was inspecting the tractor he found that all the pulleys on the drive system were slightly worn, he replaced the pulleys, put belt back on and it worked like a charm. The customer was and is tickled and has recommended my son to others for their repair needs.

Not saying that this is your problem but it is possible and should not be ruled out. :thinking:

Thanks for the input. I didn't change the upper drive belt. Will do that. The pulleys do have some wear. I'll take them off and take a light skim cut to clean them up, or replace them if their really bad.
 
Thanks for the input. I didn't change the upper drive belt. Will do that. The pulleys do have some wear. I'll take them off and take a light skim cut to clean them up, or replace them if their really bad.

I like the repair attitude on this forum! I've been repairing stuff over replacing the item for a long time.
 
Thanks for the input. I didn't change the upper drive belt. Will do that. The pulleys do have some wear. I'll take them off and take a light skim cut to clean them up, or replace them if their really bad.

If you take any off of the pulley you will most likely have to go to a smaller belt size. The pulleys are not that expensive. Shoot me a pm if ya need parts and I can give ya the part numbers.

The other drive belt can be real fun to change, on some units you will have to unbolt and lower the transaxle to change that upper belt.
 
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