Automatic Transmissions (GA6HP19Z/GA6HP26Z): Notes
BMW has developed an automatic six speed gearbox together with ZF (Zahnradfabrik Friedrichshafen), designated the GA6HP19Z/GA6HP26Z for the E60. It represents a further development of transmission technology in BMW automatic gearboxes. These gearboxes make an important contribution to the features of the E60.
The mechanical power transmission of the gearbox has been optimized with regard to gearshift comfort, quality and reduced fuel consumption. The engine torque is transferred to the gearbox by a torque converter with a controlled lockup clutch. The six forward gears and the reverse gear are produced by a Lepelletier planetary gear train. The gears are shifted by multi-disc clutches.
The GA6HP19Z and GA6HP26Z transmissions are based on the same design, they feature different torque converters and clutches. On the E60, the drive stages and the parking lock are controlled directly by the selector lever in the center console. See Fig 1 .
The E60 automatic gearboxes have the following advantages:
- Designed as a 6-speed gearbox with an overdrive ratio in 5th and 6th gear, reducing fuel consumption.
- The 6-speed gearbox allows for more gear spread, improving vehicle acceleration.
- The number of interfaces has been reduced by using the Mechatronics Module for the electronic transmission.
- Lifetime oil fill. See Fig 2 .