yesturday i was driving my car with 4 other people in it and i hit a good size bump. after i hit that bump my buddy in the back of my car whos ridden in it tons of times said it sounds like your car is reving higher. i didnt notice it till later that night when i drove my car. The car drives the exact same but, there is just this whinning noise coming from the back when i am accelerating. my other buddy said it sounds like the exhaust system...or muffler and help would be apreciated.