JD 4640 oil in trans get hot after 45min.

crmfarms · Feb 25, 2011

I have a JD 4640 that after 45mins of running the trans. oil over heats. I have the rockshaft piston out and it looks ok the control valve off and the O rings look good. Could it be the pump down in the diff.?

twopop · Feb 25, 2011

no,not the supply pump.you probably have a o-ring leak oin one of the high pressure points in the hyd.system.unless the 3-point was bobbing up and down,probably not the piston.could be the control vale,the steering valve or the selective control valves.

Tx Jim · Feb 26, 2011

High pressure internal leak as twopop stated. Feel for heat or get a thermal scanner. The trans pump isn't the problem. Leaking valves in the SCV's probably are the problem.

Andy C · Feb 26, 2011

My son's 4255 had hot oil as one of the symptoms a few years ago. The other symptom was that one of the SCV's was not working properly. I had that thing apart at least five times thinking I was missing something in the seals. Then as I was cleaning it I noticed a hairline crack on one of the machined surfaces. A closer look revealed that the crack went right on back thru the valve body.Replaced that and no more hot oil!
Good luck,
Andy

Huskers86 · Feb 26, 2011

I have a 4650 that did that and it was a tube inside the transmission that got a hole in it and bypassed the oil. We sent it in and they split the tractor and repaired it. It is a powershift trans I don't know if it would do this with the quad range or not. Good luck.

JD 4640 oil in trans get hot after 45min.

crmfarms

New User

twopop

Well-known Member

Tx Jim

Well-known Member

Andy C

Member

Huskers86

Well-known Member

Similar threads