Component Tests and General Diagnostics

Front Differential Diagnosis

1. Block the right front and rear wheels.
2. Turn the Ignition ON - Do not start the engine.
3. Place the transmission in NEUTRAL.
4. Shift the transfer case into 4 LOW.
5. Engage the rear differential lock switch.
6. Engage the front differential lock switch.
7. Raise the left front and left rear wheel off the ground and support with safety stands. Refer to Lifting and Jacking the Vehicle (Service and Repair).
8. Attempt to rotate the left front wheel 1 full revolution clockwise and counterclockwise by hand.

* If the wheel does not rotate 1 full revolution in either direction, the locking differential is engaging properly.
* If the wheel rotates more than 1 revolution in either direction, the locking differential is not engaging properly.

9. Disengage the differential lock switchs.
10. Attempt to rotate the left front wheel 1 full revolution clockwise and counterclockwise by hand.

* If the wheel rotates 1 full revolution in either direction, the locking differential is disengaging properly.
* If the wheel does not rotate more than 1 revolution in either direction, the locking differential is not disengaging properly.

11. If the locking differential is not functioning properly, remove the differential and determine the cause of failure. Refer to Differential Carrier Assembly Replacement (Service and Repair) and Front Differential Case Assemble (With E-Locker) (Front Differential Case Assemble (With E-Locker))Front Differential Case Assemble (Without E-Locker) (Front Differential Case Assemble (Without E-Locker)).