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 machine. 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 in Caterpillar machines. Dispose of all fluids according to local regulations and mandates.

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Illustration 1	g00503569
(1) All wheel drive control valve (2) All wheel drive solenoid valve (3) Forward pressure port (4) Reverse pressure port

1. Install a 1U-5756 Hose Assembly and a 8T-0857 Pressure Gauge on the forward pressure port (12) . Position the gauge in the cab for viewing during machine operation.

2. Start the engine. Run the engine at high idle.

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Illustration 2	g00503570
(5) All wheel drive control

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Illustration 3	g00503571
(6) Transmission modulator pedal

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Illustration 4	g00503572
(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) . 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. Stop the machine and shut off the engine. Remove the 8T-0857 Pressure Gauge and install a 8T-0860 Pressure Gauge on forward pressure port (3) .

6. Start the engine and run the engine at high idle. Depress the transmission modulator pedal (6) and shift the transmission direction and speed control to first speed forward. You must be on hard pavement. Release transmission modulator pedal (6) . 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.

7. Stop the machine and shut off the engine. Remove the 8T-0860 Pressure Gauge and the hose assembly from forward pressure port (3) .

8. Install a 1U-5756 Hose Assembly and a 8T-0857 Pressure Gauge to reverse test port (4) .

9. Start the engine. Run the engine at high idle.

10. 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.

11. Release transmission modulator pedal (6) . 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.

12. Stop the machine and shut off the engine. Remove the 8T-0857 Pressure Gauge and install a 8T-0860 Pressure Gauge on reverse pressure port (4) .

13. Start the engine and run the engine at high idle. Depress transmission modulator pedal (6) and shift the transmission direction and speed control to first speed reverse. You must be on hard pavement. Release transmission modulator pedal (6) . 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.

14. Stop the machine and shut off the engine. Remove the pressure gauge and the hose assembly from reverse pressure port (4) .