79 ford 545 power shifter isssue

[stevengrost]

I have a 79 ford 545 industrial tractor, looks alot like a backhoe. It has a power reversing transmission. It quit working. It guit shifting to forward and reverse. Removed steering and fuel tank. Removed inspected and cleaned saftey shift interlock blocker valve. Pulled and polished the two barrel pins on pump housing, on Transmission. Lubed and cycled the shifted several times, it operated just fine. When I put the barrels in it would not shift at all. This unit has no electronic saftey and can be shifted without the engine running or battery connected. I have spent 5 hrs talking to a guy with JUST ANSWERS Sunday he could not figure it out. I have had the unit 4 months and worked it harder than it has worked in last 5 years, so I keep finding issues, but am very satisfied with it capability

 

[stevengrost]

This is where the pins go in . M and S classic tractors has an excellent YouTube on this but doesn't cover my problem.

 

[TractorTech]

Welcome to TBN.
Attached is the blocking valve operation.
Under troubleshooting, one reason it won't move is that the blocker valve spring(s) are too weak or broken.
I can't think of anything else.

 

[stevengrost]

I haven't gotten to the blocker valve yet. Just dropping in the blocker valves #2 will not let the rod shift. Seems like it would shift the tractor was off before I had the issue but now I am wondering if it was just spool in the shift linkage or maybe the pins sticking. They were hard to get out, but after I polished them and used some koil and anti size mix, they jump out when I pass a magnet over them.

 

[stevengrost]

Spool was slop... auto correct

 

[TractorTech]

I haven't gotten to the blocker valve yet. Just dropping in the blocker valves #2 will not let the rod shift. Seems like it would shift the tractor was off before I had the issue but now I am wondering if it was just spool in the shift linkage or maybe the pins sticking. They were hard to get out, but after I polished them and used some koil and anti size mix, they jump out when I pass a magnet over them.

Sticky pins are usually the problem, but the valve spools are likely gummy too.

 

[stevengrost]

Finally got it back together it would go in reverse only. Opened the test port and blew the gunk out of it and cleaned it. Still reverse only . Tore it back down and cleaned the pins and blocker valve again, and flushed It with some break cleaner. Reassembled and it shifts perfectly. AND THEN..... after an hour of moving dirt it guit pulling. I let it rest and it worked for a while. Now it will not pull in forward or reverse. Dropped the out riggers and the wheels trunk slowly at high rpms. Moves in first On flat ground like it trying to take off in fourth gear up hill. Any suggestions? I don't want it to be the torque converter. But feel like it is.

Sticky pins are usually the problem, but the valve spools are likely gummy too.

 

[TractorTech]

Finally got it back together it would go in reverse only. Opened the test port and blew the gunk out of it and cleaned it. Still reverse only . Tore it back down and cleaned the pins and blocker valve again, and flushed It with some break cleaner. Reassembled and it shifts perfectly. AND THEN..... after an hour of moving dirt it guit pulling. I let it rest and it worked for a while. Now it will not pull in forward or reverse. Dropped the out riggers and the wheels trunk slowly at high rpms. Moves in first On flat ground like it trying to take off in fourth gear up hill. Any suggestions? I don't want it to be the torque converter. But feel like it is.

Most likely slipping clutches caused by leaking seals OR bad oil pump causing low oil pressure. Once the oil heats up, it thins out and lowers the pressure.

The low pressure is probably why the locking pins were not disengaging.