Earlier models equipped with 3-speed automatic transmission (AT) ZF 3HP 22. The latest models use a 4-speed ZF 4HP 22 or ZF 4HP EH electronically controlled automatic transmission.
Due to the complexity of clutch mechanisms and hydraulic control systems, as well as the need to use special tools for overhauling AT, this work is usually not done in a home garage. Therefore, only general descriptions of troubleshooting procedures, routine maintenance, adjustment, and removal and installation of the transmission are included in this Chapter.
If the AT needs a general repair, it should be left to a BMW dealership or a transmission repair shop. To save money, you can remove and install the transmission yourself, but remember that most troubleshooting tests require the transmission to be in the vehicle.
If you decide to replace the transmission with a new one or a remanufactured one, first make sure it fits your vehicle. The transmission identification plate is located on the left side of the casing, directly behind the selector lever.