I have a 160 WH where the auto shift pin slips out of the hole in tranny front plant . I put it back in and it will work fine for a short time, then it comes out. I've put washers behind pin shaft to move it deeper in to hole ,but it still slips out. Could the tractor frame be moving away from tranny? Is the tranny bolted to the tractor frame? Could the bolts be lose,letting the two shift around and the pin to come out? It only takes a short time to repair, but when it's -30 any time is to long.