JD 4200 won't go forward or backwards and PTO won't function

[Zebrafive]

Forward and Reverse do not work. PTO cut out at the exact same time. The rest of the hydraulics work perfectly, so I ruled out the pump.

The pumps you ruled out are the steering pump and implement pump, which supplies rockshaft (3pt hitch) and SCVs. They are not part of the hydro drive.

Going through the repair manual and the only component I'm seeing that could affect the forward/reverse and PTO would be the hydrostatic motor. I'm trying to figure out how to test this without splitting the tractor; has someone on here had this go out on a similar model?

There is an engine driven hydrostatic pump that supplies the hydrostatic motor, both are internal.


Does your Tech Manual tell where there are any test ports to check for pressure? Is it a JD Tech Manual?

 

[super55]

My understanding is there is a charge pump thats on the side of the engine that then goes to the hydro pump. I believe this also runs the power steering but it almost sound like the charge is lacking pressure or there is a valve in relief.

The F/R relief valves and I think the charge pump relief valve are all right under the floorboard right next to the where the hydro filter is. This is also the place where you run your pressure tests.

If all mechanical linkage has checked out. I would say the next step would be doing some pressure test.

 

[Surveyor4200]

Will your FEL or 3ph work? If not, your driveshaft Ujoint likely broke. Happened on my JD 4010. Nothing would work. Steering does, but hard.

Ralph

Yes, all of the hydraulics work just like before.

 

[Surveyor4200]

The pumps you ruled out are the steering pump and implement pump, which supplies rockshaft (3pt hitch) and SCVs. They are not part of the hydro drive.




There is an engine driven hydrostatic pump that supplies the hydrostatic motor, both are internal.


Does your Tech Manual tell where there are any test ports to check for pressure? Is it a JD Tech Manual?

Yes, I believe I found the procedure while looking through the manual yesterday afternoon; but I haven't had a chance to test it yet. The tractor failed on top of a sketchy pond dam, so I've got to get it pulled out of there and up to my shop to take a look. It never happens in a convenient manner, right?

 

[Surveyor4200]

My understanding is there is a charge pump thats on the side of the engine that then goes to the hydro pump. I believe this also runs the power steering but it almost sound like the charge is lacking pressure or there is a valve in relief.

The F/R relief valves and I think the charge pump relief valve are all right under the floorboard right next to the where the hydro filter is. This is also the place where you run your pressure tests.

If all mechanical linkage has checked out. I would say the next step would be doing some pressure test.

I think you're right on this, so I will get a high pressure gauge to perform the tests. I believe I saw the pressure to read was around 6,000 PSI in my tech manual. Thanks for the help.

 

[Zebrafive]

Yes, I believe I found the procedure while looking through the manual yesterday afternoon; but I haven't had a chance to test it yet. The tractor failed on top of a sketchy pond dam, so I've got to get it pulled out of there and up to my shop to take a look. It never happens in a convenient manner, right?

If the tractor does not have a neutral position? Find out what has to be done BEFORE pulling it. The only hydrostatic drive I have is my Lawn tractor and it has lever to release something (a valve?) so you can roll it with engine not running.

 

[beenthere]

There is a neutral position, as well as a low, medium, and fast "gear" selection.
Be sure that it is in one of these positions and not caught in between.. which can happen but don't know if that would cause the results the OP has going on here.

 

[Surveyor4200]

If the tractor does not have a neutral position? Find out what has to be done BEFORE pulling it. The only hydrostatic drive I have is my Lawn tractor and it has lever to release something (a valve?) so you can roll it with engine not running.

It has a neutral position on the gear selector, but I will check in the repair manual for towing considerations before doing anything. Thank you for the advice, though.

 

[Surveyor4200]

There is a neutral position, as well as a low, medium, and fast "gear" selection.
Be sure that it is in one of these positions and not caught in between.. which can happen but don't know if that would cause the results the OP has going on here.

I was really hopeful this was the issue, but I cycled through A, B and C gears and no movement.

 

[Zebrafive]

There is a neutral position, as well as a low, medium, and fast "gear" selection.
Be sure that it is in one of these positions and not caught in between.. which can happen but don't know if that would cause the results the OP has going on here.

Thanks, I was not sure if it has a neutral position.