Hydrostatic Issue - Dealer says replace - About $8000

[pmsmechanic]

Subscribed.

 

[stingray1]

Any updates?

 

[BleedingOrange]

A second opinion is NEVER a bad thing. Glad to read that you are getting one.
I would be asking for the diagnosis and solution to be put in writing, including estimated costs of all material and labor.
Scammers are less likely to want to document stuff, especially IF they are trying to rip you off.
Hopefully tractor repair shops are not becoming as bad as vehicle repair shops, with false claims and repairs.
Like someone else mentioned earlier, please keep us informed on what the real fix is, and cost, versus your first guesstimate.

 

[mike48130]

Like said above, you need to check the charge pressure first, but that is tied to the power steering, so if the steering is good, you probably have enough pressure. There is a pressure relief valve that controls the hydrostatic trans pressure, you need to add shims to it to adjust. There is a seat there that might be damaged. Located under the center of the tractor next to the test ports. The hydrostatic trans is a pump and motor just bolted together. It is probably rebuildable, but not thru JD. My 4210 has a Sauer Danfoss tag on the trans I noticed when I was under there.

I just rebuilt a pump on a Bobcat, and when it was bad there was a chopping feeling when driving and loss of power on one side. These are usually variable piston pumps with piston or gear pumps. When a piston goes bad, it becomes a leak thru, but only when that piston is moving or should be moving fluid. It does not go away, if it is bad, it is bad.

The E part of all this is just a 12VDC coil that moves a magnetic hydraulic valve spool. Current controls the amount of movement of the spool. The spool sends the hydraulic fluid to a cylinder that moves the angle of the swash plate on the piston pump that controls the volume and thus speed. There is a test in the service manual for these I think.

When I first got my 4410, I noticed it was considerably slower than my neighbors 4410, so that is why I know most of this from testing mine. My pressure was low, and I adjusted the pressure to be right.

There is an order in which you need to check the pressures and such, and a good mechanic will do that so they know the whole story.

1100 hrs seems low for a trans to go out. I have 1100 on my 4410 and it is very strong.

I hope it is not bad, that is a big bill.

 

[texasranger556]

Like said above, you need to check the charge pressure first, but that is tied to the power steering, so if the steering is good, you probably have enough pressure.

In my case the steering worked fine but charge pressure was low which caused the transmission to chatter at low engine RPMs. It ended up the charge relief valve that had jammed open. Removed it and re-assembled, fixed the issue.

The steering relief valve opens at 1500 psi then dumps to the charge circuit which reliefs at 100-150 psi.

I agree with the rest of your post.

 

[dfkrug]

It ended up the charge relief valve that had jammed open. Removed
it and re-assembled, fixed the issue.

Did you have to buy a new charge RV? Is the charge RV adjustable, or fixed (welded) to keep you
from adjusting it? How did it fail?

 

[texasranger556]

Did you have to buy a new charge RV? Is the charge RV adjustable, or fixed (welded) to keep you
from adjusting it? How did it fail?

From my understanding it's just a plug holding a spring into a round piece of steel that presses into the orifice to maintain charge pressure. It was my dad who actually took it out and he said the spring felt like it was jammed off center somehow. No clue how it got like that, but simply re-installing was enough to fix the issue, that was about 100 hours ago and still runs great.

You can add shims.

 

[mike48130]

Here is the picture from the service manual.

It should be part number LVA12615 on the parts diagram I think. You need to order the shim kit which I don't see.

Part Number: LVA12615
Remarks: CHARGE RELIEF VALVE, (SUB FOR LVA11862) (ALSO ORDER LVU14595)

 

[Daves_Farm]

We’re you ever able to get the second opinion? What was the final result? Mine is not nearly that bad, but I’d be interested to know what came of it.

Thanks

 

[Kubota 2350]

Must have gotten it fixed, seems once the problem is solved, you hear no more about it.
I too would like to know the final outcome.