JD L120 Transmission

[Purerock Racing]

just an update on my mower, turns out after I put the unit up on jack stands and started looking around, one of the drive belt tensioner pulleys had fallen apart. Not sure how other than maybe a bearing in the pulley had frozen up. Anyhow, I replace both pulleys and also a new belt and what do you know, this thing rocks like new again. I guess you can't have any slippage in the drive belt to the trans or it won't work at all.

 

[Rivets]

That's the prime reason the first thing to check is the belt and idler/tensioner pulley. A drive belt does not have to be cracked or have chunks missing to go bad. If the belt has not been replaced in the last three years, do that first. As far as the tranny goes, sealed does not mean non fixable. It means that the average person should not try. Unless you know what you are doing and understand that if something goes wrong (there is plenty of things that can) it could get very expensive. Average price for me to rebuild a basket case is $300 plus parts. I would not advise any homeowner to do so. As EngineMan said, it's a job. Advising someone that they can do it, when you have not done it yourself, is bad advise. At least once a year I get one in a basket, because someone tried to do it, even with a manual and failed.

 

[ILENGINE]

The first thing that needs to be checked when you have drive problems is belts and pulleys. I agree with Rivets, that unless you have done more than one, stay out of the transmission, and let somebody with experience work on it. Even when a professional works on them, sometimes things still go wrong. I was doing one a few years and while torquing the center section pulled the threads out of the case, and hadn't reached recommended torque. things can go wrong quickly, and when they do it gets expensive immediately.

 

[BuzzGold]

Hello to the forum new guy here hoping to save someone money. ( My first post)
I have a JD L-120 that has 535 hrs. I am a maintenance junkie. I started noticing the usual problems with the drive system. Slowing, no reverse etc...
Since the belt was new I checked the usual things and determined the transaxle was going. After pricing them / rebuilding I was at a quandary.
Try this before spending a fortune or scraping the thing...Change the fluid, unless you had a leak and it ran dry.

If the old fluid doesn't smell burnt or have metal filings in it, there is hope....
Originally they used 10-30w. motor oil. The new unit's recommend synthetic. Since I only use this in the summer I opted for straight 30w.
I dropped the transaxle tires and all in an hour, cleaned and pried out the rubber plug / vent and drained the old oil.
The old fluid didn't smell burnt and wasn't gritty with metal so I was hopeful.

I refilled the unit with 2+ qts of oil. Rotate the wheels once in awhile as you re-fill to purge air pockets. Shove the plug back in, hook up the linkages and brackets and off you go. 2 1/2 hrs was all it took! It runs like new. Hope I can save someone else from this dilemma. Any question please ask be glad to help!

-Buzz

 

[bertsmobile1]

I don't want to rain on your parade Buzz but all you have done is postponed the inevitable.
Expect it to run another season or two then repeat the previous problems.
There is no seal between the cylinder block which rotates and the swash plate that does not rotate.
Oil has to pass between these two plates which is how the control system works.
Even without any particulates in the oil plain old errosion will wear the mating surfaces.
You might even go to 20w 50 full synthetic which is better than the strait 30.

OTOH, the repair is to fit new pump & engine so you may as well wring the last bit of life out of yours.
How long the heavier oils work will depend upon how bad it got when you replaced the oil.
I did one for customer who mows around 5 to 6 hours in a single day and he noticed it was going a little slower towards the end on the day.
Put 20W 50 in it and its been going strong for 3 seasons so far.
Another customer said they were having the same problem so I tried it with them and his did not last a single season.

Good thing is you now know yours is on the way out so you can keep an eye out for a cheap replacement,
Every now & then they come up cheap at surplus warehouses.

I just replaced a T 40J.
Tuff torque quotes 2 to 3 months for either the kit or a new tranny.
Was going to order one from the USA ( currently discounted $ 250 ) then found out JD had them in stock with a day turn around,
Worked out $ 350 dearer for the customer but he is old and mowing is about the last thing he can still manage to do so mentally he needs to do it.

 

[BuzzGold]

I don't want to rain on your parade Buzz but all you have done is postponed the inevitable.
Expect it to run another season or two then repeat the previous problems.
There is no seal between the cylinder block which rotates and the swash plate that does not rotate.
Oil has to pass between these two plates which is how the control system works.
Even without any particulates in the oil plain old errosion will wear the mating surfaces.
You might even go to 20w 50 full synthetic which is better than the strait 30.

OTOH, the repair is to fit new pump & engine so you may as well wring the last bit of life out of yours.
How long the heavier oils work will depend upon how bad it got when you replaced the oil.
I did one for customer who mows around 5 to 6 hours in a single day and he noticed it was going a little slower towards the end on the day.
Put 20W 50 in it and its been going strong for 3 seasons so far.
Another customer said they were having the same problem so I tried it with them and his did not last a single season.

Good thing is you now know yours is on the way out so you can keep an eye out for a cheap replacement,
Every now & then they come up cheap at surplus warehouses.

I just replaced a T 40J.
Tuff torque quotes 2 to 3 months for either the kit or a new tranny.
Was going to order one from the USA ( currently discounted $ 250 ) then found out JD had them in stock with a day turn around,
Worked out $ 350 dearer for the customer but he is old and mowing is about the last thing he can still manage to do so mentally he needs to do it.

Bert,
I appreciate the info. I kind of figured that might be the case. Just hopeful it gets me by until winter when new mowers are cheaper.
This thing is worn out and once you start throwing money at one of these throw away mowers it seems to never end.