Functional Inspection - AWD System

All-Wheel Drive (AWD) System Functional Inspection
Functional Inspection 1
Functional Inspection 1 is a mechanical system inspection for both the left and right side gerotor pumps, pistons, and clutch packs and will assist in determining if:
^ The clutch pump check valve is in the "open" position.
^ The left and right side gerotor pumps have the ability to "pull" fluid from the sump and send pressurized fluid to the left and right side clutch pack pistons.
^ The left and right side pistons will engage the specific side clutch packs.
^ There is a mechanical connection between the rear differential ring and pinion, the propeller shaft, the transfer case, and the transmission assembly.
1. Raise the vehicle on a hoist. Lift the vehicle in a manner that will allow all four wheels to rotate during testing.
2. Start the engine.
3. Move the gear shift lever to the NEUTRAL position.
4. Rotate, by hand, a rear wheel in a forward direction. If the All-Wheel Drive (AWD) system mechanical components are functioning properly, the front wheels will rotate at the same speed.
5. Rotate, by hand, the opposite side rear wheel. If the All-Wheel Drive (AWD) system mechanical components are functioning properly, the front wheels will rotate at the same speed. Failure of the front wheels to rotate during this test may indicate a "closed" clutch pump check valve, malfunctioning gerotor pump, piston, clutch pack, or valves internal to the unit.

Functional Inspection 2
Functional Inspection 2 is a mechanical system inspection for both the left and right side gerotor pumps, pistons, and clutch packs and will assist in determining if:
^ The clutch pump check valve is in the "open" position.
^ The left and right side gerotor pumps have the ability to "pull" fluid from the sump and send a variable and progressive rate of pressurized fluid to the left and right side clutch pack pistons.
^ The left and right side pistons will engage the specific side clutch packs at a progressive rate.
^ There is a mechanical connection between the rear differential ring and pinion, the propeller shaft, the transfer case, and the transmission assembly.
1. Raise the vehicle on a hoist. Lift the vehicle in a manner that will allow all four wheels to rotate during testing.
2. Start the engine.
3. The gear shift lever should be in the PARK position.
4. Rotate, by hand and in a forward direction, a rear wheel at a slow rate of speed. Rotation of the wheel should be possible.
5. Rotate, by hand and in a forward direction, the opposite side rear wheel at a slow rate of speed. Rotation of the wheel should be possible.
6. Rotate, by hand and in a forward direction, a rear wheel at a fast rate of speed. A properly operating pump, piston, and clutch pack will activate and create a progressive increase in wheel rotational resistance.
7. Rotate, by hand and in a forward direction, the opposite side rear wheel at a fast rate of speed. A properly operating pump, piston, and clutch pack will activate and create a progressive increase in wheel rotational resistance. Failure to feel a progressive rate of resistance may indicate a "closed" clutch pump check valve, malfunctioning gerotor pump, piston, clutch pack, or valves internal to the unit.

Functional Inspection 3
Functional Inspection 3 is a mechanical system inspection for both the left and right side gerotor pumps, pistons, and clutch packs and will assist in determining if:
^ The clutch pump check valve is in the "open" position.
^ The left and right side gerotor pumps have the ability to "pull" fluid from the sump and send a variable and progressive rate of pressurized fluid to the left and right side clutch pack pistons.
^ The left and right side pistons will engage the specific side clutch packs at a progressive rate.
^ The rear differential has the ability to provide rear wheel torque and override the resistance created by the parking brake assembly.
^ There is a mechanical connection between the rear differential ring and pinion, the propeller shaft, the transfer case, and the transmission assembly.
1. Raise the vehicle on a hoist. Lift the vehicle in a manner that will allow all four wheels to rotate during testing.
2. Start the engine.
3. Move the gear shift lever to the DRIVE position.
4. Accelerate the vehicle lightly until all four wheels are rotating at an equal slow speed.
5. Depress the parking brake slightly, gradually increasing the parking brake retention to create resistance in the rear wheels. The rear wheels should stop spinning. The front wheels should remain spinning.

Important: Do not accelerate the vehicle with the parking brake applied for a period longer than 5-7 seconds.

6. Lightly depress the accelerator pedal, increasing engine rpms in order to determine if the rear wheels can provide enough torque to "override" the resistance created by the parking brake assembly. Failure of the rear wheels to rotate during this test may indicate a "closed" clutch pump check valve, malfunctioning gerotor pump, piston, clutch pack, or valves internal to the unit.