[4]

Toro LX425 Surging

TomS

Active User
H-M Supporter - Gold Member ($25)
Joined
May 20, 2013
Messages
1,869
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
 

Rbeckett

Silver
Rest In Peace
Joined
Sep 24, 2010
Messages
2,605
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
 

TomS

Active User
H-M Supporter - Gold Member ($25)
Joined
May 20, 2013
Messages
1,869
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.
 

TomS

Active User
H-M Supporter - Gold Member ($25)
Joined
May 20, 2013
Messages
1,869
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
 

Goat Driver

Active User
Registered
Joined
Dec 27, 2012
Messages
36
Is your engine hard to start at times? ......like it has a weak battery?
 

Goat Driver

Active User
Registered
Joined
Dec 27, 2012
Messages
36
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
 

TomS

Active User
H-M Supporter - Gold Member ($25)
Joined
May 20, 2013
Messages
1,869
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.
 

DAN_IN_MN

Active User
Registered
Joined
Aug 7, 2013
Messages
657
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.
 

Goat Driver

Active User
Registered
Joined
Dec 27, 2012
Messages
36
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.
 

TomS

Active User
H-M Supporter - Gold Member ($25)
Joined
May 20, 2013
Messages
1,869
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 carefully inspected every pulley in the drive system. The only one that has any detectable wear was the the variable speed pulley. The wear was very minor and unfortunately the outer pulley half sheaves are welded to the shaft so I wasn't able to machine them.

Put everything together and no change. The tractor free wheels on downhill grades and the slipping gears/ratcheting sound is still there. For clarification the tractor pulls fine in forward and reverse on flat ground and uphill grades. I'm leaning towards the notion that the problem is in the differential even though the Toro dealer said it was OK. I'm stumped!!!
 

TomS

Active User
H-M Supporter - Gold Member ($25)
Joined
May 20, 2013
Messages
1,869
Here is a link to an exploded parts diagram of your transaxle.

TORO LX425 SINGLE SPEED TRANSMISSION ASSEMBLY

[/QUOT


Yep, that's it. The differential is riveted so I wasn't able to disassemble and inspect the internals. I was able to see that none of the gear teeth were bad. Wasn't able to determine how the axle shafts drive the spider gears (splines I assume) and that's where I think my problem is. What puzzles me is if one or both axle splines are bad then why does the tractor drive uphill without the differential slipping?
 

DAN_IN_MN

Active User
Registered
Joined
Aug 7, 2013
Messages
657
Is the shift lever adjust correctly so the transmission is fully in gear? I have a feeling that your shift dogs are jumping out of gear.
 

Goat Driver

Active User
Registered
Joined
Dec 27, 2012
Messages
36
Is the shift lever adjust correctly so the transmission is fully in gear? I have a feeling that your shift dogs are jumping out of gear.

that was my thought too, DAN_IN_MN...or...wear on the bevel gears and /or clutch collar may be restricting the full movement of the shifting assy on the splined gear shaft.
 

TomS

Active User
H-M Supporter - Gold Member ($25)
Joined
May 20, 2013
Messages
1,869
that was my thought too, DAN_IN_MN...or...wear on the bevel gears and /or clutch collar may be restricting the full movement of the shifting assy on the splined gear shaft.
First of all thanks to you and others for helping me work through this. For what it's worth I adjusted the shift lever per the Toro maintenance manual, or at least I think I did. I'll play with the adjustment and see if it has any effect.

Thanks again.
 

DAN_IN_MN

Active User
Registered
Joined
Aug 7, 2013
Messages
657
First of all thanks to you and others for helping me work through this. For what it's worth I adjusted the shift lever per the Toro maintenance manual, or at least I think I did. I'll play with the adjustment and see if it has any effect.

Thanks again.

No problem Tom.

Have you tried kept your hand on the shift lever while it's acting up? You might be able to feel it jumping around if it is the shift dogs jumping in and out.

Does it do this only with a load on it or with it's own weight also?

How steep of an incline is it?

Do you think you may be pulling too much with it? (I don't have a clue as to what you've been pulling.)

How long have you owned this tractor?

Any recent change of drivers?

I have a similar tractor that I replaced the shift dogs with used ones. I know it still slips. It's been a few years and I don't remember at what state I left that project at. Just trying to let you know that others have been down this road.
 

TomS

Active User
H-M Supporter - Gold Member ($25)
Joined
May 20, 2013
Messages
1,869
No problem Tom.

Have you tried kept your hand on the shift lever while it's acting up? You might be able to feel it jumping around if it is the shift dogs jumping in and out.

Does it do this only with a load on it or with it's own weight also?

How steep of an incline is it?

Do you think you may be pulling too much with it? (I don't have a clue as to what you've been pulling.)

How long have you owned this tractor?

Any recent change of drivers?

I have a similar tractor that I replaced the shift dogs with used ones. I know it still slips. It's been a few years and I don't remember at what state I left that project at. Just trying to let you know that others have been down this road.
Good point about the shift lever. I'll play with it and see if anything changes.

To answer your questions; it slips with or without load; the incline varies from very mild to moderately steep; heaviest load I've pulled is about 200 lbs so I don't think I've been pulling too much weight; the tractor came with my house I bought about a year ago and has about 150 hours on it; I do most of the driving and try not to abuse it. I did inspect the forward/reverse gears and there was no wear marks on the gear teeth tips that would indicate slippage. The forward/reverse drive dogs didn't show signs of slippage either.

Thanks
 

TomS

Active User
H-M Supporter - Gold Member ($25)
Joined
May 20, 2013
Messages
1,869
SUCCESS!!!!!!!!!!!!!!!

I went back through the Toro shifter mechanism adjustment just to make sure I did it correctly, which I did. What I didn't notice was that the plastic shift detent insert on the fender wasn't allowing the shifter rod to fully engage the forward/reverse shaft in the forward position. Thanks to Goat Driver and DAN_IN_MN for staying with me on this and suggesting I manually hold the shifter in the forward position. Had I not done this I wouldn't have noticed the shifter wasn't fully engaged. The tractor doesn't free wheel on down hills anymore. Man am I glad this is over!

Thanks again Goat Driver an DAN_IN_MN.
 

DAN_IN_MN

Active User
Registered
Joined
Aug 7, 2013
Messages
657
SUCCESS!!!!!!!!!!!!!!!

I went back through the Toro shifter mechanism adjustment just to make sure I did it correctly, which I did. What I didn't notice was that the plastic shift detent insert on the fender wasn't allowing the shifter rod to fully engage the forward/reverse shaft in the forward position. Thanks to Goat Driver and DAN_IN_MN for staying with me on this and suggesting I manually hold the shifter in the forward position. Had I not done this I wouldn't have noticed the shifter wasn't fully engaged. The tractor doesn't free wheel on down hills anymore. Man am I glad this is over!

Thanks again Goat Driver an DAN_IN_MN.
You're welcome Tom, great to hear you got it figured out! :thumbsup:
 

crazydually

Newbie
Registered
Joined
Sep 28, 2013
Messages
4
It seems I have the same problem but before I got to this thread I pulled my transmission off to make sure I didnt have any broken parts inside, when I pulled it apart I noticed water inside, my question now is what type of grease do they use in the transmission cause right now it is black and soupy, their are parts in their that look to be a red looking grease and I was wondering if the color change was from the water getting in, I have had no luck finding anyhing about what kind of oil or grease that goes inside any of these type of transmission, it is the single speed transmission from a Toro LX425, also on the same subject what would be a recomended way of cleaning out all the old grease, hope someone can help on this cause my grass is getting tall.
 

TomS

Active User
H-M Supporter - Gold Member ($25)
Joined
May 20, 2013
Messages
1,869
It seems I have the same problem but before I got to this thread I pulled my transmission off to make sure I didnt have any broken parts inside, when I pulled it apart I noticed water inside, my question now is what type of grease do they use in the transmission cause right now it is black and soupy, their are parts in their that look to be a red looking grease and I was wondering if the color change was from the water getting in, I have had no luck finding anyhing about what kind of oil or grease that goes inside any of these type of transmission, it is the single speed transmission from a Toro LX425, also on the same subject what would be a recomended way of cleaning out all the old grease, hope someone can help on this cause my grass is getting tall.
I got a tube of grease from my local Toro dealer, about $12 if I remember correctly. This is a slurry type grease; not thin like oil but not thick like axle grease. Somewhere between the two.

Cleaning the internal parts is a messy process. I used mineral spirits and a brush to get everything clean and ready for assembly. Be sure to use a good quality gasket sealer when assembling the cases. It keeps the grease in and water and dirt out. I used Right Stuff made by Permatex. Not cheap but good.

Hope this helps.


Tom S
 

crazydually

Newbie
Registered
Joined
Sep 28, 2013
Messages
4
Thanks I'll go that route, what I have been able to research is the only gearbox grease I can find is Stens "00" grease used in Snapper mowers but seams to be what im looking for since I went to a local repair shop and they said they havnt had to tear down many transmissions and didnt know what to use which sounds like alot of bull and they just dont want to tell me so they can do the work but I'll update on how this turns out.
 

crazydually

Newbie
Registered
Joined
Sep 28, 2013
Messages
4
Just wanted to update what I did so if anyone else has to rebuild a lawn mower trany this could help, I found on Ebay Stens "00" grease which seems to be what is used in the transmissions but I didnt want to wait for shipping so I found some corn head grease at my local John Deer farm supply store which is "0" weight but works, I watched some YouTube video's where someone used Red and Tacky #2 grease which is to thick and locked up his reverse, well after tearing down cleaning and reassembling it runs like new with no problems, on a extra note I used two tubes of grease costing just under $5, hope this helps anyone else cause after alot of research their is not much online help for this and I wish I had video logged this but maybe next project I will, and thanks to Tom for the help.
 

TomS

Active User
H-M Supporter - Gold Member ($25)
Joined
May 20, 2013
Messages
1,869
Glad it worked out for you.
 
[5] [7]
Top