TRANSMISSION   722.6 in MODEL 170, 202, 208, 210     without touch shift TRANSMISSION   722.6 in MODEL 129, 140

Operation The hydropneumatic transmission control is dived into electronic and hydraulic transmission control. While the electronic transmission control is responsible for gear selection and for matching the pressures to the torque to be transmitted, the transmission's power supply control occurs via hydraulic elements in the electrohydraulic control module. The oil supply to the hydraulic elements, such as the hydrodynamic torque converter, the shift elements and the hydraulic transmission control, is provided by way of an oil pump connected with the torque converter.

The electronic transmission control (ETC) allows for the precise adaptation of pressures to the corresponding operating conditions and to the engine output during the gearshift phase, resulting in a noticeable improvement in shift quality. It is possible to reach the engine rpm limit in the individual gears with full throttle and kick-down. The shift range can be changed in the forward gears while driving, but the electronic transmission control (ETC) employs a downshift safeguard to prevent over-revving the engine. The system offers the additional advantage of flexible adaptation to different vehicle and engine variants. The driver can choose between the two transmission modes S (Standard mode) and W (Winter mode). These also provide different gear ratios for reverse gear.