GF27.60-P-2002CWQ Transmission Control, Function

GF27.60-P-2002CWQ Transmission control, function
- TRANSMISSION 722.9

The transmission control is divided into the electronic and hydraulic transmission control functions. Whilst the electronic transmission control takes over the gear selection and adaptation of pressures to the torque to be transmitted, the power supply of the transmission is controlled via the hydraulic elements of the electrohydraulic controller unit. 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 to the torque converter. The fully integrated transmission control (VGS) makes possible precise adaptation of pressures to the respective operating conditions and to the engine output during the shift phase which results in a significant increase in shift quality. It is possible to reach the engine rpm limit in the individual gears using full throttle and kickdown.

The shift range can be changed in the forward gears while driving. The fully integrated transmission control prevents an unacceptably high engine speed by a downshift security device. Furthermore the fully integrated transmission control offers the advantage of a flexible adaptation to various vehicle and engine versions.

On vehicles with code (494) USA version the driver can choose between the 2 transmission modes "S" (sport program) and "C" (comfort program).

On vehicles except code (494) USA version the driver can choose between 3 transmission modes "S" (sport program), "C" (comfort program) and "M" (manual program). These also provide different gear ratios for reverse gear.

The fully integrated transmission control control unit (Y3/8n4) monitors and shifts depending on:
^ vehicle speed
^ gear selector switch position
^ accelerator pedal position
^ transmission mode selection
^ condition of the transmission
^ selected gear, with mode "M" (on vehicles except code (494) USA version)
^ signals on the drive train CAN