Working/lubrication/shift pressure, function - GF27.60-P-3024AHS
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 working/lubrication/shift pressure, general
- Circuit 87 ON
- Circuit 61 (engine running)
Working/lubrication/shift pressure, general
The oil pressures are separated into:
- Working pressure
- Lubricating pressure
- Shift pressure
Working pressure
The oil pressure produced by the oil pump is converted into working pressure by the working pressure regulating valve. The level of working pressure depends on the position of the regulating valve and therefore on its geometry.
The position of the working pressure regulating valve is influenced by the working pressure control solenoid valve (VGS) (Y3/8y1) in a manner which is dependent on load and gear. All other pressures required for the transmission control are derived from the working pressure.
On model 216 as of model year 2011 /YoM 10 model refinement package / model 221 as of model year 2011 /YoM 10
The optimized working-pressure reduction for the new generation of automatic transmissions enables lower braking power and therefore reduces the fuel consumption.
Lubricating pressure
At the working pressure regulating valve excess oil is diverted to the lubrication pressure regulating valve and from there used in a regulated manner for lubrication and cooling of mechanical transmission parts and the torque converter.
In addition the pressure in the torque converter is limited via the lubrication pressure.
Shift pressure
The shift pressure (pressure in the multidisk clutch or in multidisk brake) is derived from the working pressure.
The respective control solenoid valve influences the position of the associated regulating valve. In turn the position influences the pressure prevailing in the multidisk brake or in multidisk clutch. The pressure thus depends on the geometry of the respective regulating valve.
On model 216 as of model year 2011 /YoM 10 model refinement package / model 221 as of model year 2011 /YoM 10, with code (B03) ECO start/stop function.
The electric transmission oil pump (M42) safeguards the hydraulic system's oil supply when the engine is switched off. This is actuated through the gear oil auxiliary pump control unit (N89).
| Overview of system components for automatic transmission (AT) | GF27.10-P-9992AHS |