Allis FWD 8050 Powershift Issues

Got a good one for you guys. Tractor quit moving so the powershift was pulled and hauled into the local dealer for a "rebuild". Got it back and installed it in the tractor. Worked for 5 hours then quit again. Dealer wouldn't warranty because they just got the powershift and not the whole tractor so we decided to split it. Found that there was multiple piston seals ripped. Replaced all the seals and reinstalled in the transmission. Its been working for over 50 hours now however its developed a random problem. It will be driving and happens in any range or powershift. It acts like someone shifted the transmission into neutral and it just coasts to a stop. The range and powershift were not moved nor the clutch pressed it will be driving just fine and then coast to a stop. If i mess with the range/powershift it will start going again. Sometimes its 5 minuets and sometimes its 45 minuets. Removed range transmission cover and when it acts up all the range gears stop turning but you can still hear the hum of the clutch drums turning so I'm convinced its in the powershift somewhere. Also when it acts up the steering, brakes, and pto all still work just wont move. All clutch pressures are perfect to spec when it acts up as well. Any ideas are greatly appreciated.  

Sorry for the late reply I'm not very tech savvy. Checked pressure at all 1/8" pipe plugs for the a,b,c,d clutch's and when the tractor stops moving. Each clutch pressure does not drop. Stays good at 210psi which according to the manual is the correct pressure. Doesn't matter if the oil is cold or hot the result is still random. When the tractor stops moving with the range cover off of the top of the transmission. The gears stop turning but i can hear the hum of the powershift clutch packs still turning. It seems like there is a disconnect from the range transmission to the powershift. When i seen it split it looks like there was only a collar connecting the two but the splines were in great shape and there is no grinding noise at all when its driving or stopped. When i shift the powershift gears i can hear it shift in the powershift. rpm light on the dash works and does go out when required. Powershift valve was gone through and also replaced as the dealer had the parts cannon out .   

This may be out of left field. Just thinking of anything that might help. It semms to me the inching valve is dumping pressure on the clutches causing the tractor to stop. Sinc you have had it apart i think id go through the procedure to adjust the inching valve to factory spec. That thing is sensitve and it doesnt take much to throw it off. You may have slready done that i dont know. Trying to think of anything to keep you from having to split it again

Ok i also agree that it seems the powershift is working but i find it weird how the coupler could come undone and then slide back on. I was wondering what connects the input shaft from the engine to the range transmission. Does it go flywheel clutch pack then output shaft of powershift, then coupler, then range. Like what's the path of power maybe that'll help pinpoint this. I would like multigauge set like that but i only have a single gauge set as the multi is pricy. 

Actual clutch pressures will vary with oil temps and engine speed. 210 psi is fine. That isn't your problem. If it was under 100 psi there would be a problem.  Place the PST in 3RD gear and leave it there. It is mandatory to have TWO gauges, and a hose on each gauge. Wire the gauges to the head light or battery box or whatever, so that you can SEE the gauges while driving. Have the two gauges plugged into the C-1 test port and A-2 test port. Now, drive the tractor until it quits moving and tell me what the gauges say. The inching pedal absolutely must be fully UP !!  Any downward position of the inching pedal cuts off oil flow to C-1 and A-2 inching clutch packs. When the tractor quits moving, does the red 1800 RPM light come on ??? and both gauges dip to zero ???   *****  The small inner transmission drive shaft goes from the torque limiter disc all the way thru the rear end and powers the hydraulic pumps. You always have power steering, right ??  so there is no problem there. And the larger drive coupler just cannot disconnect itself and reconnect itself. There has to be a hydraulic problem of some kind.

Edited by DrAllis - 3 hours 59 minutes ago at 6:09am

Ill go get another fitting as i have enough gauges but not enough of the fittings. drove around yesterday for an hour before it did it. Red light never came on and usually never does. then it did it after 10 mins of driving, very hard to pinpoint when it does it as its so random. Inching pedal does come all the way up and can watch the spool operation is correctly in and out as well as it response to the percent of clutch pedal travel correctly. the first time it disconnected was in reverse and the second was in 4th. Moved the gear shifter from low range to high and it instantly started working again. Second time i moved the range in all different spots as well as the powershift then it randomly started working again. pto and power steering all still work when the tractor stops moving. Does the large drive coupler just connect the powershift or also the hydraulic pumps?

So another question what does the output shafts jobs do on the powershift. like outside shaft vs inside shaft? 

ok that makes more clear to me now. I will go test those clutchs and report back. May be while getting the fitting and waiting for it to act up

Anything is possible at this point. I have adjusted the cables multiple times even removed and used a ratchet strap to make sure it was fully pulled into the range gear made no difference