Sent in one of my 88 D50 trans to get rebuilt and waited 9 months, it would popped out of 1st and 3rd plus it would grind when putting it into gear.

So I get it back, put it back in and it still pops out of the forward gears and now it won't go into reverse even? I thought I had another shifter to try but the other trans has a shorter shaft on the shifter and the transfer case shifters. It seem to go over to the reverse spot but still tries to go forward?

Anybody got a clue or good guess what a guy can do?