JD 540B powershift problem

thedewaltcar17 · January 23, 2019, 09:18:46 PM

I have a 1980 540B with a powershift trans in it. It had a bad motor and sat for almost 2 years. after rebuilding the motor I got it running and shifted into forward gears. none of them ( 8 ) work, but all 4 reverse gears do work. I changed the filter and cleaned the intake screen but it didn't change. supposedly the trans was fine when the engine blew. Any ideas before I pull the motor back out???

Firewoodjoe · January 24, 2019, 03:58:28 AM

Couldn't you check pressures before u pull engine or any other major tear down?

mike_belben · January 24, 2019, 07:40:48 AM

Find the FWD/REV valve and see if you can manually stroke the thing full stroke without getting run over. Also squirts some 90 weight gear oil on the spool shafts to hopefully seep in.

Im betting time evaporated every bit of oil from the control circuitry and now there is too much clearance space for correct pressures inside until they get some oil. If my tired old dozer sits, reverse takes a while of fwd operation to engage. If i start it next day, no issue. Powershift trannies that have inching valves or modulators can have all sorts of little pistons that balance two pressures to engage a function or divert flow to a cooler or internal lube circuit. Internal surface rust can wreak havoc inside valving too.

If you can drive it in circles in reverse and especially on hills to get oil circulated, fwd may come back.

Grandpa · January 24, 2019, 07:58:19 AM

If the machine has been sitting I would suspect the forward/reverse shift cable.
At least I think that machine has cables, it has been awhile since I looked at one.

thedewaltcar17 · January 24, 2019, 08:44:51 PM

I drove it backwards up a long hill and rolled back down 5 times or about an hour last week, it didn't get any better. The cables all function to where they go into the trans. it's been in the garage all week I'm going to see what's up tomorrow and if it's still the same ill try pressure test.