The drivers door has always shut with a bit of a rattle,Z4's are known for it. However, If I waggle the open door backwards and forwards I can hear a thumping noise just like there is a lump of metal loose in the bottom of the door. I'm assuming that the window motor is loose.Has anyone else had this problem and is there an easy fix,or do I need a new motor?. I've tried to remove the door card, but cannot get all the clips out and am not wanting to force it and break it. Is there a specific order to remove the clips from the door card, and do you need a special tool? I'd like to try to fix in myself before I spend money with a dealer as I'm ok with basic mechanicals.