Common issues & diagnosis
Transmission are a problematic part in all makes of vehicle—and unfortunately BMW is no exception.
BMW has used many different transmissions across the years, but here are some common issues in their more modern vehicles:
- E-Generation autos: Basically all automatic transmissions used in the later E-Generation vehicles were problematic—but it’s not worth us going into this deeply as a transmission issue in one of these cars will just about kill it now—but generally speaking they’d have problems with gears, valves, solenoids and mechatronics.
- F and G-Generation ZF 8-speeds: The later F and G-Generation vehicles predominantly use ZF 8-speed transmissions. These are much more reliable than the autos used in the E-Generation—but they are prone to some gear wear and we have seen a few mechatronics failures.
- F and G-Generation FWDs: The more recently adopted FWD (and FWD-based AWD) transmissions introduced in the F39 X2 and X1 F48 haven’t developed any issues yet, but it’s also too early to tell.
- Late manuals: The manual transmission used in later E-Generation and on are pretty robust in our experience—but we don’t have enough on the road in Australia for us to be an authority.
According to the mechanics we work with, most modern automatic transmission issues can be resolved with a transmission control unit reset. In some vehicles this can be done without diagnostic tools, as shown in this video.
What is the part's function?
Broadly speaking the transmission manages the engine’s power through a series of gears, then outputting that power to the wheels via the rest of the drivetrain.
The varying gear ratios of the transmission are it’s primary feature—enabling the vehicle to travel at different speeds.
Modern automatic transmission use a mechatronics to control the internal mechanics—they are effectively the brain of the transmission.
How to determine fitment compatibility
Each model generation will typically have a few different types of transmission to account for different engines and drivetrains, etc.
Transmission hardware compatibility can be determined by matching the BMW part numbers from the catalogue, but it doesn’t take into account firmware and ISN (a form of VIN locking)—which is a major obstacle when installing second-hand ZF 8-speeds. In these scenarios with ZF 8-speeds we typically virginize the transmission to remove the ISN and update the firmware.
If you are looking for a replacement transmission you will need to supply your vehicle’s full 17-digit VIN along with a description of your transmissions fault.
Interchangeability between models
Transmissions are often interchangeable between vehicles sharing a common platform.
