Differential Lock: Testing and Inspection

Fig. 1 Select drive vacuum control system. Eagle:

1. Disconnect vacuum harness from front axle shift motor.
2. Connect suitable vacuum pump to shift motor front port.
3. Apply 15 inches of vacuum to shift motor and rotate right front wheel to fully disengage axle.
4. Shift motor should maintain vacuum applied to front port for minimum of 30 seconds. If motor does not maintain vacuum, replace motor. If motor does maintain vacuum, proceed to next step.
5. Disconnect vacuum pump from shift motor front port. Connect pump to shift motor rear port, cap transfer case connecting port, and apply 15 inches of vacuum to motor.
6. Shift motor should maintain vacuum applied to rear port for minimum of 30 seconds. If shift motor does not maintain vacuum, replace motor. If motor does maintain vacuum, proceed to next step.
7. Remove cap from shift motor transfer case connecting port and check for vacuum at this port. If vacuum is not present, refer to next step.
8. Rotate right front wheel as necessary to be sure that axle has shifted completely. Axle must be shifted completely in order to open shift motor connecting port.
9. Check vacuum at shift motor transfer case connecting port again. If vacuum is still not present, replace shift motor. If vacuum is present at port, refer to "System Diagnosis."