I have an intermittent "clunk" noise that appears to be coming from up in the rear roof area when I go a gentle bump (like going over uneven pavement pulling into driveway). It's almost as if there is a large ball bearing up there that rolls around and clunks every once in a while. I've tried opening/closing the sun roof and have bounced up and down on the rear of the vehicle to try to replicate... but no luck.. It's almost as if something hits the roof when going over a bump... but there's nothing there that hit the roof... ARG!!!! Anybody else run into the mysterious roof "clunk"?