Clunk Noise When Slowing
 

Hey everyone. I drive an '04 X3 with a manual transimission. My car has this odd problem. When I come to a stop and I'm in gear, the car will sort of jolt a little forward making a clunking sound. It only seems to happen when in gear, not in neutral. When coming in for a different repair, the BMW technician said it may be the differential. I wanted to know if anyone else had this issue and knew how much it was to fix it? I really hope the entire differential won't need to be replaced. Thanks for any help you can provide.