On a John Deere 640 Log Skidder serial #337998 will 100 PSI through the charge pump operate the transmission OK? It shifts OK and doesn't slip. The book says 175 PSI for new spec.
Clutch lockup occurs at approximately 90 psi so the pressure really needs to be addressed. Does this unit have a winch with the 11 inch drum? If so, disconnect the pressure line to the winch and cap off the pressure port and recheck your pressure to see if it comes up.
Hi mg2361, and thank you for replying to my Trans pump problems. I disconnected the winch oil supply. The pressure stayed the same as before at around 100PSI. I also swapped a couple different gauges, but they all read around 100 PSI. I also added a few shims to the pump pressure regulator valve. This bumped the pressure up a bit but no more than 5 to 10 PSI. I guess without pulling the engine and C1-C2 clutch packs, to get at the pump, I dont know what else to do. The machine still runs and operates, but as the oil warms up the pressure trails off.
Hi, The trany sump screen and filter were clean.
Check the transmission filter relief valve. If that is sticking it may cause low transmission pressure.
Hi , I checked all 4 of those spools in that valve assembly. They were all clear and workable, not scored. Is there another valve where the actual transmission pressure can be increased? Thank U 4 responding, any advise will be greatly appreciated.
If you depress the clutch pedal does the transmission pressure increase?