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| Illustration 1 | g00908137 |
(1) Piston pump (2) Control piston (3) Makeup and line relief valves (4) Servo valve (5) Proportional solenoid valve (6) Pilot spool | |
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| Illustration 2 | g00911874 |
Section A-A (7) Swashplate (8) Actuator (5) Proportional solenoid valve (two) (9) Port (pump oil) (10) Wire Connector to electronic control module (ECM) (11) Input shaft (12) Pistons (nine) (13) Barrel assembly (14) Port (pump oil) | |
All wheel drive piston pump (1) is in the all wheel drive system. Piston pump (1) is a variable displacement axial piston pump that is fastened to the transmission. A drive on the transmission uses power from the engine in order to turn input shaft (11). Input shaft (11) turns barrel assembly (13) and nine pistons (12) .
The pressure sensor is located in front of the flushing and cooling control valve. The flushing and cooling control valve sends a pressure signal to the all wheel drive pressure sensor. The all wheel drive pressure sensor converts the pressure signal into a pulse width modulated signal (PWM). Then, the all wheel drive pressure sensor sends the PWM to the all wheel drive electronic control module (ECM). The ECM processes this information and the ECM sends a signal to all wheel drive piston pump (1). Piston pump (1) will increase the pressure or piston pump (1) will decrease the pressure.
Actuator (8) and the pressure sensor work together in order to control the amount of oil flow and the direction of oil flow from the piston pump. This is accomplished by controlling the direction of swashplate (7) and the degree of tilt for swashplate (7). When the charge oil is sent to two of four actuator pistons, swashplate (7) will tilt. The tilted swashplate causes pistons (21) to move in and out of the barrel assembly. As the barrel assembly turns, the movement of the pistons causes oil flow from either port (9) or port (14). Signal oil pressure at port (9) causes oil flow from port (14) and a signal oil pressure at port (14) causes oil flow from port (9). The two main relief valves limit the pressure to approximately 41300 kPa (6000 psi).
For additional information, refer to Systems Operation, "Pump Control (All Wheel Drive)".