JD L120 hydro transaxle failure

[hmacken1]

All,

First off, thanks for taking a look at this to help me find the proper step forward!

My L120 rear transaxle is out. There is nothing either forward or reverse. I have search through the internet to find some answers but have landed here to get the real scoop.

What are my options?
Rebuild kit? Is this even worth the time?
Will any other rear ends work in the L120? Any with the same rear end? Any with ones that will also fit?
An I stuck with a 4-500$ bill if I want to keep this mower?

I am pretty handy but want to make sure I am not wasting my time.

Much appreciated!

Henry

 

[Rivets]

Before going into big bucks, have you checked the simple things first. Condition of the belt and might it have come off? Condition of the idler pulleys and tensioner arm. Does the arm move freely and are the pulleys in good condition? If any of these are questionable, I would replace first, because if I do want to repair the tranny thes3 should be done also.

 

[StarTech]

Also that disengage rod is proper place. And if you recently remove a rear wheel that the axle key is in place.

 

[hmacken1]

I will start there and let you guys know. I would be surprised if its any of those.

 

[bertsmobile1]

And one last check to be made
with the engine OFF and the bake on slip your fingers up under the transmission pulley or over the top of it so you can feel the shaft
turn the pulley ans see if the shaft turns with it
The pulley is on a fine spline which rips out over time .


As for trannies I used to use Mulligans very nice & HONEST people to deal with. Know their stuff and will steer you in the best direction.
!20's should be good for 1000 hours .
Then the tranny starts to wear, it becomes very noisy and gradually looses power.
a sudden loss of drive is something broken .

It is not uncommon for the belt to pop off the pulley and sit between the pulley & fan so it looks like it is on properly.
If the dive belt is working properly you should be able to turn the engine over by moving the belt if the belt slips it is not tight enough.

 

[tom3]

These transmissions are famous for failure, but don't usually quit completely. When pushing in on the little rod that sticks out the back, rock the tractor back and forth some to ensure the coupling is engaged.

 

[xray man]

This is a little late on response time. I just happened to see your post. My 120 trans started slipping and growling. I pulled it out (you can't check fluid level in it), drained it, removed bolts and separated them. Checked the gears, all good,refilled with synthetic 5w-50 motor oil per somebody's instructions I came across on YouTube. Used some Permatex gasket stuff to put trans case back together. It's working fine. I've put about 70 hours on it. Hope this helps.

 

[xray man]

What I was told was that the factory puts budget brand 10w30 when they're built and when you get some viscosity breaking down it loses its grip inside. And it sure enough fixed mine. I don't guess you have to split the case. I suppose jyou could drain it out of the fill hole. But it's probably a good idea to see how the gears look and there will be a small amount of metal shavings in the bottom unless you had a gear really damaged. You'll be able to see it.

 

[xray man]

Mine went out at just below 500 hours.

 

[bertsmobile1]

What I was told was that the factory puts budget brand 10w30 when they're built and when you get some viscosity breaking down it loses its grip inside. And it sure enough fixed mine. I don't guess you have to split the case. I suppose jyou could drain it out of the fill hole. But it's probably a good idea to see how the gears look and there will be a small amount of metal shavings in the bottom unless you had a gear really damaged. You'll be able to see it.

You were told rubbish
JD has them filled with 10W 30 so they will work anywhere in the country from the frozen north to the desert south.
The usual oil is 20w40 for a new box and 20w50 for an old one, both fully synthetic .
Over time the addatives that make a multi grade oil multigrade break down so when hot the oil gets too thin.
I would never use 5W oil in a JD tranny no mater how much it is sold for .

There is no "Grip" in any way shape or form inside a hydro box.
When you had it apart you should have seen that all it is a a bunch of pistons running inside a rotating cylinder block.
So it is all pumping , the pump is a piston pump and the motor is a piston pump working backwards .

When the oil breaks down it leaks out from between the bottom of the cylinder block & plate it runs on which has no seal.
A fluid under pressure will always take the path of least resistance
So it can either push the motor piston or leak out the side whichever is easier .
Over time the surface finish of the sliding surfaces polishes and gets smoother so it provides less resistance to the oil flowing out .
The place for repeating tosh is Twitter & facebook this forum runs on facts.