Ford 550 backhoe tranny problems

[Yellowhair42]

My cousin has a Ford 550 but it says 555 on the hoe.It's 1977 vintage and has a powershift tranny.Here's the problem,it sporadically has issues moving under it's own power.Some days it works just fine an others it wont move no matter what.Sometimes he can get it to move if he puts the stabilizers all the way down and engages the tranny and revs it for a while to get the wheels turning.We thought something like the oil pickup line inside came off but why would it work just fine occasionally?Anybody out there have similar problems or have an idea what might be wrong?Thanks for looking.

 

[TractorTech]

Assuming the fluid is at the correct level, it sounds like a seal on the clutch piston is leaking, allowing the clutch to not engage. Revving it up would allow enough pressure to develop so that the piston engages. This is the case if it is doing it in one direction. Both directions would indicate possibly the pump is weak. Either way, when the oil get hot and thin, the problem can get worse.
The pickup on the pump is bolted to the housing and it is pretty unlikely it has broken off. The filter in that housing comes unglued and falls to the bottom on older units, but wouldn't necessarily cause that problem.
Is the shift linkage sloppy? Check all the way to the top of the bell housing where it goes in. The roll pins get worn and sloppy which doesn't allow the spool to shift all the way in to place.

 

[Yellowhair42]

Assuming the fluid is at the correct level, it sounds like a seal on the clutch piston is leaking, allowing the clutch to not engage. Revving it up would allow enough pressure to develop so that the piston engages. This is the case if it is doing it in one direction. Both directions would indicate possibly the pump is weak. Either way, when the oil get hot and thin, the problem can get worse.
The pickup on the pump is bolted to the housing and it is pretty unlikely it has broken off. The filter in that housing comes unglued and falls to the bottom on older units, but wouldn't necessarily cause that problem.
Is the shift linkage sloppy? Check all the way to the top of the bell housing where it goes in. The roll pins get worn and sloppy which doesn't allow the spool to shift all the way in to place.

Shifter is not sloppy.You can feel it engage.Why would some days it be fine and others not?It's hit or miss on this and we can't pin it down to anything because it's inconsistent.You would think that once there is a problem it would always happen.We would like to at least get an idea before comitting to fixing it.