GF27.57-P-1000AHC Oil Supply For Automatic Transmission, Function

GF27.57-P-1000AHC Oil Supply For Automatic Transmission, Function
- TRANSMISSION 722.9 in MODEL 207

Function requirements for automatic transmission oil supply, general

^ Circuit 87 (connected circuit 15) ON

Oil supply for automatic transmission, general

With the combustion engine running, the primary pump delivers oil to the electrohydraulically controlled automatic transmission. The oil pump drive is provided through the torque converter's drive flange.

The pump is installed in the transmission bell housing behind the torque converter.

Oil supply for automatic transmission with stopped internal combustion engine (with code (B03) ECO start/stop function)

On vehicles with an automatic transmission with electrohydraulic control and an oil pump driven via the drive flange of the torque converter, the oil supply stops when the internal combustion engine is switched off. With this, all the control elements and actuators change to a basic state under no load and the automatic transmission power flow stops.

When the internal combustion engine is started, and the oil supply has been built up, the gear position has to be changed from "N" to "D". The resulting time delay between the starting request and the starting period is reduced with the transmission oil pump (M42).

The electric transmission oil pump is actuated via the transmission oil auxiliary pump control unit (N89) when switching the internal combustion engine on and off. When the internal combustion engine is switched off, the electric transmission oil pump takes over the oil supply of the control elements and actuators of the automatic transmission.

For code (B03) ECO Start-stop function

The electric transmission oil pump also supports the primary pump at low internal combustion engine speeds.