1989 Century hard shift on first shift only

When I first put the car into drive or reverse the engine jumps with a loud poping noise. While driving there are no other problems. If I go back to park or nuetral and then back in any gear it does the hard shifting again.


I orginally firgured it was the motor/trans mounts but after replacing them all, the same thing happens.

3.3 liter engine.