For 1990-2009 cars

### Removal Procedure

1. Apply the parking brake.
2. Block the vehicle wheels.
3. Drain all of the air reservoirs. Refer to Air Brake Reservoir Draining .

Important: Tag the air lines for later installation.

4. Remove the air lines at the differential lock control valve. Refer to Hose and Line Replacement - Nylon Push-In Type Fitting .
5. Disconnect the wiring harness connector.
6. Remove the following components from the differential lock control valve:

• | The nuts

• | The washers

• | The bolts

• | The differential lock control valve

### Installation Procedure

1. Install the differential lock control valve.

Notice: Refer to Fastener Notice in the Preface section.

2. Install the following components to the differential lock control valve:

• | The bolts

• | The washers

• | The nuts

Tighten
Tighten the nuts to 13 N·m (115 lb in).

3. Connect the wiring harness connector.
4. Install the air lines at the differential lock control valve. Refer to Hose and Line Replacement - Nylon Push-In Type Fitting .
5. Start the engine.
6. Inspect for air leaks. Refer to Air Brake System Testing .
7. Verify proper operation of the inter-axle differential lock.
8. Remove the wheel blocks.