Nag1 Automatic Transmission (Service Information): Pump-Oil: Operation

Fig 1: Identifying Oil Pump Components

Courtesy of DAIMLERCHRYSLER CORP.

1 - CRESCENT

2 - OIL PUMP

3 - EXTERNAL GEAR

4 - INTERNAL GEAR

5 - INLET CHAMBER

6 - PRESSURE CHAMBER

When the engine is running, the oil is pumped through the inlet chamber (5) along the upper and lower side of the crescent (1) to the pressure chamber (6) of the housing. The meshing of the teeth prevents oil flowing from the delivery side to the intake side. An external gear (3) is eccentrically mounted in the pump housing. The external gear is driven by the internal gear (4) which is connected to the torque converter hub. See Fig 1.