John Deere 490 4 roller fabtec saw chain spinning in reverse

[c greenham]

Good Day,

Got an issue which I can seem to find the problem.

The harvester is cutting wood with no big issues but having a problem with the chain spinning back ward when the saw arm retracts.  It seems as if when the saw arm starts to retract the oil is flowing also in revers in the saw motor.

What could cause this, any one experience this problem?

I have checked the check valve in the manifold it seems to be working fine the diverter cartridge looks good no o rings missing.


Thank you all for your help.

[rusticretreater]

It sounds like the seals between the control valves are leaking.  You probably need a new manifold or a rebuild. 

[fluidpowerpro]

Because I do not know the specifics of the system. I'll just share some ways I would begin troubleshooting.
What controls the motors direction. If it's a valve, what controls the valve?
A solenoid? If so is it getting a signal at the wrong time? Is voltage dropping when the arm is signaled? Low voltage could cause the valve to not hold position.
Is it pilot operated, is it being piloted at the wrong time or possibly loosing pilot signal?