Looking for parts for your BMW automatic transmission or manual transmission? You'll find many of the parts available to service your BMW's transmission here. While internal transmission servicing and rebuilding should be done by professionals, there are a lot of things on the outside of the transmission that you can service or replace yourself. These include gearbox seals, o-rings, gaskets, automatic transmission filters, backup light switches, mounting bolts, flanges, collar nuts, screw plugs, Mechatronics, and more.