Powertrain - Service Information (S63): Powertrain: Transmission: Notes

With the M Sport automatic transmission 6HP26S the customer is able to enjoy spontaneous gearshifts and a more stable control of the torque converter lock-up clutch.

To effectively absorb rotational irregularities in the drive train and achieve the best possible reduction of the slip at the converter lock-up clutch, a double-damper torque converter is installed. A single-damper torque converter design is used in the 6HP26TU of the E71 xDrive50i.

The spring characteristics in the double-damper converter are especially designed for the increased power and torque of the S63 engine. The 6HP26S internal components have also been adapted to the maximum engine speed of 6800 rpm.

The plastic transmission oil pan has been replaced with an aluminum version. The air flow to the transmission has been enhanced and the opening point of the transmission oil thermostat has been lowered.

The gear ratio is identical to that of the series production 6HP26TU transmission.

Fig 1: Identifying E70/E71 M Aluminum Transmission Oil Pan

Courtesy of BMW OF NORTH AMERICA, INC.