4450 shift question

[Ken Henry]

A neighbor has a 4450 with 12,000 hrs but well cared for tractor. Row crop work only. The problem is the powershift trans will change gears on its own in either forward or reverse. Cab mounts don't seem to be bad. I'd appreciate ideas on what to check. Thanks in advance for you help.
Ken

 

[Tx Jim]

I've never heard of the manually controlled PS changing gears without moving shift quadrant. I suggest inspecting shift valve and checking trans pressures.

 

[D-]

Is the lever moving?

 

[tim s]

Loose linkage ball joints can cause this too..

 

[fixerupper]

My 4650 power shift has killed the engine twice while I was in motion backing up. I assume it's this same valve but maybe not. It's only done it twice in three years of use. When I start it back up it's fine. Jim

 

[DONMYEIL]

I run a 4955 and when the trany. oil got low it would do down shifts and up shifts because the oil pump would suck air. It had an oil leak at the couplers .