
Just changed out the flex disc in my 92 325i Made the same noise you are describing. Flex disc on the bimmer, is what some would call a universal joint on other cars, is made different but serves the same purpose. Connects the transmission yolk to the drive shaft yolk. On the 92 325i it is a major pain in the butt to change. ie: exhaust and sheilds have to be moved!!
Good Luck!!