143H and 163H Motor Graders All Wheel Drive Caterpillar

Complete the following steps in order to determine if the pump pressure solenoid valve is functioning 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	g00503764
(1) All wheel drive pressure sensor (2) 7X-2444 Tee (3) Pump pressure solenoid valve (4) Flushing and cooling control valve

1. Install a 7X-2444 Tee in the line between the flushing and cooling control valve and the all wheel drive pressure sensor. Install a 4J-5477 O-Ring Seal and a 8T-0861 Pressure Gauge to the tee.

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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

2. 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 forward. Set torque control lever (7) to the MINIMUM position. Move all wheel drive control (5) to the MANUAL position. Release transmission modulator pedal (6) . The pressure gauge should be at 5500 ± 700 kPa (800 ± 100 psi) .

3. Move torque control lever (7) to the MAXIMUM position. Watch the pressure gauge as torque control lever (7) is moved. As torque control lever (7) moves toward the MAXIMUM position, the system pressure should increase. When torque control lever (7) is in the MAXIMUM position, the pressure gauge should be at 35200 ± 700 kPa (5100 ± 100 psi) .

4. Repeat Step 2 and Step 3 with the transmission and speed control in first speed reverse.

5. Stop the machine and shut off the engine. If the pressure from the all wheel drive piston pump is not correct, check pump pressure solenoid valve (3) . Pump pressure solenoid valve (3) may have a faulty solenoid, a sticking valve or a worn valve.

6. Remove the pressure gauge, the tee and the O-ring seal from the machine.