hey guys, yesterday my room mate rear ended my car and he ended up in a 10 foot ditch with his girl in the car so all in all i was the lucky one in this situation. But after getting the wrecker to tow him out, and after the police left, i've noticed a knocking the back of my car thats very annoying. I've heard it before but i can't remember what was causing it. It's like something is knocking against the underside of my car every time i hit the smallest bump. I believe him rear ending me may have knocked the exhaust slightly out of place and now its jostling around and hitting the underside of my car. Does this sound like the most likely scenario or should i be more worried?