143H and 163H Motor Graders All Wheel Drive Caterpillar

Complete the following steps in order to determine if the all wheel drive solenoid valve is operating properly.

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NOTICE
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

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Illustration 1	g00781577
(1) Control valve for the all wheel drive (2) Drive solenoid (3) Forward pressure test port (4) Reverse pressure test port

1. Install Tooling (A) on the forward pressure port (3). Position the gauge in the cab for viewing during machine operation.

2. Start the engine.

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Illustration 2	g01070164
(5) All wheel drive control

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Illustration 3	g00861143
(6) Transmission modulator pedal

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Illustration 4	g00781613
(7) Torque control lever

3. Depress transmission modulator pedal (6) and shift the transmission direction and speed control to first speed forward. Set torque control lever (7) to the MINIMUM position. Turn all wheel drive control (5) to the MANUAL position.

4. Release transmission modulator pedal (6). Run the engine at high idle. The pressure will rise momentarily above 10000 kPa (1450 psi). Then, the pressure will drop to 5500 ± 700 kPa (800 ± 100 psi). If the pressure is not correct, inspect all wheel drive solenoid valve (2). Check for a faulty solenoid, a sticking valve or a worn valve.

5. Depress the transmission modulator pedal (6) and shift the transmission direction and speed control to first speed forward. You must be on hard pavement. Turn all wheel drive control (5) to the MANUAL position. Release transmission modulator pedal (6). Run the engine at high idle. Move torque control lever (7) to the MAXIMUM position. The pressure gauge should read 35000 ± 700 kPa (5100 ± 100 psi). If the pressure is not correct, inspect all wheel drive solenoid valve (2). Check for a faulty solenoid, a sticking valve or a worn valve.

6. Stop the machine and shut off the engine. Remove Tooling (A) from forward pressure port (3) .

7. Install Tooling (A) on reverse test port (4) .

8. Start the engine.

9. Depress transmission modulator pedal (6) and shift the transmission direction and speed control to first speed reverse. Set torque control lever (7) to the MINIMUM position. Turn all wheel drive control (5) to the MANUAL position.

10. Release transmission modulator pedal (6). Run the engine at high idle. The pressure will rise momentarily above 10000 kPa (1450 psi). Then, the pressure will drop to 5500 ± 700 kPa (800 ± 100 psi). If the pressure is not correct, inspect all wheel drive solenoid valve (2). Check for a faulty solenoid, a sticking valve or a worn valve.

11. Depress transmission modulator pedal (6) and shift the transmission direction and speed control to first speed reverse. You must be on hard pavement. Turn all wheel drive control (5) to the MANUAL position. Release transmission modulator pedal (6). Run the engine at high idle. Move torque control lever (7) to the MAXIMUM position. The pressure gauge should read 35000 ± 700 kPa (5100 ± 100 psi). If the pressure is not correct, inspect all wheel drive solenoid valve (2). Check for a faulty solenoid, a sticking valve or a worn valve.

12. Stop the machine and shut off the engine. Remove Tooling (A) from reverse pressure port (4) .