Precaution, Rear CV Axle Bolts
 

This post is for precaution:

please check the rear cv axles on your X5s for loose or missing bolts.

My 2003 4.4i was making clicking noises from the rear end. clicking was synchronize with the car moving. so i suspected it was in the wheel. as i inspect the wheels, i noticed one the head on one of the bolts going into the rear axles was broken and the clip or gasket was dangling and hitting the exhaust pipe. two other bolts were 2/3 of the way out, so i tightened the bolts and will be replacing the broken bolts.

i don't know if anyone has experience this. but check your bolts as a sense of precaution.