Sounds like the player may have had a good movement of internals. Remember the insides are precise pieces that need to all work together and a hard jarring is not always the best thing for them. You can either talk it to the dealer and have it replaced (not sure if a rebuild auto has a warranty or not) or check e-bay and just get a new factory stereo.
How bad was your car hit before it was rebuilt?
How bad was your car hit before it was rebuilt?