Oil Pump

DESCRIPTION

Fig. 10:

Fig. 11:

Fig. 12:

Fig. 13:

The oil pump (Fig. 10) is located at the front of the transmission inside the bell housing and behind the transmission front cover. The oil pump consists of two independent pumps (Fig. 11), a number of valves (Fig. 12), a front seal (Fig. 13), and a bolt on reaction shaft. The converter clutch switch and regulator valves, pressure regulator valve, and converter pressure limit valve are all located in the oil pump housing.

OPERATION
As the torque converter rotates, the converter hub rotates the oil pump drive gear. As the drive gear rotates both driven gears, the clearance between the gear teeth increases in the crescent area, and creates a suction at the inlet side of the pump. This suction draws fluid through the pump inlet from the oil pan. As the clearance between the gear teeth in the crescent area decreases, it forces pressurized fluid into the pump outlet and to the oil pump valves.
At low speeds, both pumps supply fluid to the transmission. As the speed of the torque converter increases, the pressure output of both pumps increases until the primary pump pressure reaches the point where it can close off the check valve located between the two pumps. When the check valve is closed, the secondary pump is shut down and the primary pump supplies all the fluid to the transmission.

CONVERTER CLUTCH SWITCH VALVE
The converter clutch switch valve is used to control the hydraulic pressure supplied to the front (OFF) side of the torque converter clutch.

CONVERTER CLUTCH REGULATOR VALVE
The converter clutch regulator valve is used to control the hydraulic pressure supplied to the back (ON) side of the torque converter clutch.

TORQUE CONVERTER LIMIT VALVE
The torque converter limit valve serves to limit the available line pressure to the torque converter clutch to approximately 120 psi.