hey all new here.sctatching my head on this one.410 g powershift no 1st or 2nd f or r...3rd n 4th fine.replaced shift handle to no avail.pulled shift solenoid valve body.jumped each solenoid all checks good shuttle valves move freely.pulled transmission,dissasembled 1 and 2 clutchpacks.clutches in great shape.on advice of another mechanic resealed valve body to trans and shift and control valve bodies.problem persists.one more note if you are rolling at 2mph in 3rd and shift to 2 the machine stopps abruptly.any help would be appreciated...
I've read of Cat backhoes with similar issues caused by weak batteries. Alternator overtaxed trying to charge battery and causing voltage to drop just enough to cause power shift problems. Plovbably not your problem but maybe worth checking. You may want to clean up all the electrical connectors related to the power shift system, especially under the machine where they can get corroded.
I think there may be a timer relay behind the dash, should be able to jump terminals on that to confirm issue but I'm not sure why two work and two don't.