Imported from Germany from "Zaja" from the E34 forum some steel toothed rims for the gear of the electric rear blind, the alu toothed rim always wears and then the wellknown rattle starts. Replacement from the dealer is only the complete gear with motor for much $.
We replaced it on a friends E32, and Mike (Hairywithit) made a nice instruction for that.
http://8810.teacup.com/750hiline/img/bbs/0000518.jpg


http://www.bimmerboard.com/forums/posts/266973