How much play is there supposed to be there? When I lift my car, take off parking brake and turn the drifeshft back and forth by hand; there is quite a bit of play there. Which with my six puck is causing that BANG if I engage too quickly..
Think the six puck could have possibly damaged the gears in the differential?

 

They have some play, Mine moves a lot, almost like a quarter inch to both sides.

 

my diffs axle stub have a about a 1/4 inch of play. it slips in a groove and has some play but is perfectly fine. if it doesnt leak, and the seal, stub, and oil check out ok, its fine. as i was told by a trans/diff expert, the banging is probably just the soft stock mounts. get some solid mounts and youll notice a world of difference