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

GF27.57-P-1000AHS Oil Supply For Automatic Transmission, Function
- TRANSMISSION 722.9 in MODEL 216.3 as of model year 2009 / YoM 08
- TRANSMISSION 722.9 in MODEL 216.3 (except 216.374) as of Model Year 2011 /YoM 10 model refinement package
- TRANSMISSION 722.9 in MODEL 221.0 as of model year 2009 / YoM 08
- TRANSMISSION 722.9 in MODEL 221.0 (except 221.095)
- TRANSMISSION 722.9 in MODEL 221.0 (except 221.074) as of Model Year 2011 /YoM 10
- TRANSMISSION 722.9 in MODEL 221.1 as of model year 2009 / YoM 08
- TRANSMISSION 722.9 in MODEL 221.1 (except 221.195)
- TRANSMISSION 722.9 in MODEL 221.1 (except 221.174) as of Model Year 2011 /YoM 10

Function requirements for automatic transmission oil supply, general

^ Circuit 87 (connected circuit 15) ON

Oil supply for automatic transmission, general

The oil pump (primary pump) provides the oil supply for the electrohydraulic-controlled automatic transmission with a running internal combustion engine. The oil pump drive is provided through the torque converter's drive flange. It is installed in the transmission bell housing behind the torque converter.

Oil supply for automatic transmission with stopped internal combustion engine (with model 216 as of model year 2011 /YoM 10 model refinement package or model 221 as from model year 2011 /YoM 10, with code (B03) ECO start/stop function)

If with a stopped internal combustion engine, the oil supply fails, all control elements and actuators switch to an unloaded basic status 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 electric 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.

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