143H and 163H Motor Graders All Wheel Drive Caterpillar

Complete the following steps in order to determine if the motor displacement solenoid valve is operating correctly.

Illustration 1	g00503304
The cover has been removed for photographic purposes. (1) Motor displacement solenoid valve (2) Control valve for the all wheel drive (3) Motor displacement signal port

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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.

1. Install Tool (C) in the line between motor displacement signal port (3) and the all wheel drive piston motor. Install Tool (B) onto Tool (A). Install Tooling (A) onto the pressure tap. Position Tooling (A) in the cab for viewing during machine operation.

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Illustration 2	g00861107
(4) All wheel drive control

2. Operate the machine in first speed forward through fourth speed forward and first speed reverse through third speed reverse. Operate the machine with all wheel drive control (4) in the ON position (MANUAL or AUTOMATIC). The pressure gauge should read zero.

3. Shift the machine into fifth speed forward or fourth speed reverse. The pressure gauge should read approximately 3000 ± 70 kPa (435 ± 10 psi). If the pressure reading is not correct, inspect motor displacement solenoid valve (1). The valve may be sticking or the valve may be worn. Also, the motor displacement signal line may contain blockage.

4. Stop the machine and shut off the engine. Remove all tooling.