hedberg667

well the noise is kind of like a dull thumping, it seems to thump with the idle of the engine. It comes from the rear of the car but only when the car is idling in drive if i put it in park the sound disappears. I thought it was my exhaust rattling but if so wouldn't it still make the sound when it idles in park? Id really like to find out what this sound could be to try and head off any big problems. Thanks