Shifts hard going into reverse

[jason d o]

What are all the possibilities to check when my th400 tranny hits hard going into reverse? It doesn't do it everytime only when its bound up. I'm thinking it could be the pinion preload, but how would you check that? Any possibilities would be appreciated.

[Lt.Del]

check engine AND trans mounts.   A little play and it will feel and sound like a hard shift.

Check u joints too.