I recently purchased a 2002 case 570mxt from a local dealer. When I test drove the machine , I used it for about 20 min. I told the mechanic that it had too much delay when shifting from forward to reverse. He serviced the transmission, said the filter was dirty and that it was low on fluid. He assured me it was fixed. Paid for the machine got it home and 30 min in to the first job the slow shifting came back. After an hour or so, forward would only drag a little, reverse began to work again with no delay. After 20 min or so forward came back with no delay and lost reverse. Will flip flop back and forth after that. Changed fluid and cleaned screen and filter no change. Please help!
Welcome to HEF sitefinisher! Is this a powershift or shuttleshift? You say you "cleaned screen" I am assuming a shuttleshift? Please confirm.
Thank you for welcoming me. Yes. you are correct. This is a shuttle shift, series 1 tractor. Today, I spent some time trying to narrow things down a bit. I disconnected the forward and reverse solenoids from the system. I took a 3 way toggle switch and built a temporary new circuit to run the machine without any of the relays, safety devices, or the original F-N-R switch. I got the same delay and slipping after about 20 minutes of heavy load and forward/reverse shifting. This time I lost reverse first. It is almost always forward that is lost first. I switched the order of the 2 solenoids and reverse was still the first one that slipped.
Ok that's great, you have basically eliminated most of the electrics as a fault. Your problem likely exists either in 1) the transmission control valve 2) transmission pump 3) Worn clutch packs..... The control valves have a problem with a couple of circlips/ snap rings at the modulator see this thread - & this one - The valve is easy to remove & inspect. It is possible the coils at the valve may be faulty with heat - try swapping the FWD & REV coils & see if it still affects REV first. Do these checks first, hopefully it will sort it for you. Some pressure tests will be involved with further testing - do you have any testing equipment available? 500 psi gauge will be required.
I have had the control valve off. I could not see any evidence of snap ring failure. The the spools all looked undamaged; however, we have had experience with some Cat dozer transmission control valves bench testing fine but giving trouble at random in the field causing them to fall out of gear. I did switch places with the forward and reverse coils and reverse was still the one slipping when hot. About every 6th or 7th forward / reverse shift, forward would slip and reverse would pull. I haven't tracked down a test fitting with the correct adapter to run pressures. Case offered to sell me a testing kit for $3100.00. I should be able to change all of the questioned parts for a few dollars more than that including labor labor.