when shifting from park or rev to drive if it thunks it's most likely the front diff isolator bushings. there are 2 pressed in (top and pass side #14) and 1 that bolts on the diff cover(#6). the pressed ones are notorious for going bad.
that slaming its your lower diff moving. rip your ebrake that have someone shift it from park to drive and so forth your diff should be moving about a 3 or so inches as soon as power is applied i paid like 400 bucks to get mine fixed