I have a 4-3 trans in my 86. Just after I had my clutch replaced. 1 week later, the o/d started to run in and out of gear. upand down up and down. Then it stops all together. I reset the computer, it tried to shift a few times, same thing then it stops trying.
I can control the dash light with the button on the shifter, but trans dose not move.
I checked the relay on the firewall. no problem there.
I replaced the ECM. No fix there.

I will have it back on the lift on the shop today. Any ideas of what to look for? I have the haynes manuel, not much in there about this trans. It is vague at best.

Flustered.

 

Yes, you got that right - "vague at best". Haynes' should have a round hollow binder, so you could hang it in the 'library', tear a page, read, wipe, and flush.

I don't know what to suggest on the tranny diagnostics there...