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| Illustration 1 | g06375386 |
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(1) Right forward clutch solenoid valve
(2) Right reverse clutch solenoid valve (3) Right motor proportional solenoid valve (4) Left motor proportional solenoid valve (5) Left forward clutch solenoid valve (6) Left reverse clutch solenoid valve (7) Right clutch shuttle valve (10) Left clutch shuttle valve (11) Right Forward Pressure Sensor (12) Right Reverse Pressure Sensor (13) Left Forward Pressure Sensor (14) Left Reverse Pressure Sensor | |
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| Illustration 2 | g06360938 |
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(1) Right forward clutch solenoid valve
(2) Right reverse clutch solenoid valve (3) Right motor proportional solenoid valve (4) Left motor proportional solenoid valve (5) Left forward clutch solenoid valve (6) Left reverse clutch solenoid valve (7) Right clutch shuttle valve (10) Left clutch shuttle valve | |
The All Wheel Drive control valve performs the following:
- Clutch engagement for the piston motors
- Clutch disengagement for the piston motors
- Displacement of the piston motors
- Provides a passage for free flow between the piston motors and the piston pumps
In the forward gears, the All Wheel Drive Electronic Control Module (AWD ECM) energizes solenoids (2) and (5). High-pressure oil is then allowed to flow to shuttle valves (7) and (10). This high-pressure oil shifts the shuttle valves, preventing oil from flowing to the reverse side of the circuit. The high-pressure oil then flows to and engages the clutches, locking the piston motors to the front wheels.
Proportional solenoid valves (3) and (4) provide variable control pressure to the wheel motors. The pressure is proportional to the control current from the AWD ECM. Motor displacement is reduced proportionally to the control pressure. The reduction of the motor displacement allows the motor to attain higher speeds at lower torques. The proportional solenoid is active for some conditions in gear 4F or gear 3R. The proportional solenoid is always active in gear 5F through gear 7F or gear 4R through gear 5R.
The operation of the AWD control valve in the reverse gears is similar to the operation of the AWD control valve in the forward gears. In the reverse gears, the AWD ECM activates solenoid valves (1) and (6). This activation allows high-pressure oil to be sent to shuttle valves (10) and (7). The high-pressure oil shifts the shuttle valves. The high-pressure oil prevents oil from flowing to the forward side of the circuit. High-pressure oil then flows to the clutches. High-pressure oil engages the clutches. The high-pressure oil will lock the piston motors to the front wheels.