GMC Workshop Service and Repair Manuals

Clean

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All valves, springs, bushings, pistons, control valve body, and accumulator housing in a clean solvent.

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Dry using compressed air.

Inspect

1. All valves, pistons, and bushings for:

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Porosity.

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Scoring.

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Nicks.

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Scratches.

2. Pistons for:

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Seal damage.

3. Springs for:

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Damaged or distorted coils.

4. Valve body casting and accumulator housing for:

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Porosity.

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Cracks.

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Interconnected passages.

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Damaged machined surfaces.

5. Solenoid, connectors, and switches.
6. PWM solenoid screen.

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Inspect, clean, and replace if necessary.

Control Valve Body Assembly