Transmission Identification: Notes

BMW automatic transmission are manufactured by two suppliers for the US market:

• Zahnradfabrik Friedrichshafen: Commonly referred to as ZF. ZF manufactures both manual as well as automatic transmissions.
• GM Powertrain - Hydramatic: Hydramatic is a manufacturing division of General Motors located in Strasbourg, France. Hydramatic supplies automatic transmissions to BMW for four and six-cylinder vehicles.

BMW has developed an internal numbering system for their transmissions for ordering parts, information research and identification. Also, each transmission manufacturer uses an internal identification system. Here is a breakdown of these identification codes:

Hydramatic Transmissions have internal designations, however they are not used often. The internal code for the A4S310/270R is 4L30-E and the A5S360/390R is 5L40-E. See Fig 1 and Fig 2 .