After a long run with my M5, I noticed on the road,and when pulling slowly into my driveway, that there is a "clunk" noise coming from the left rear suspension. The noise can be duplicated by kneeling up and down on the rear seat and occurs on very smooth surfaces. Any ideas what could be the cause? The shock shows no sign of leakage. The car has very low miles but of course is a '93! Rubber boots on differential look fine. Thanks for any help. Dennis.