Torque Tube Bearing & Rear Halfshaft Spline Noise

TORQUE TUBE BEARING NOISE

A "grinding" noise that changes pitch as the vehicle speed changes may be due to a worn input shaft cone and roller assembly.

1. Position the gear selector to the neutral position and set the parking brake.

2. Start the engine and slowly increase the engine RPM to 3500 RPM. If the "grinding" noise cannot be heard proceed to Step 4.

3. If the "grinding" noise can be heard, check the accessory drive belt system and air induction system. Service as required.

WARNING: DO NOT ENGAGE THE "AWD" FEATURE WHILE THE REAR HALFSHAFT ASSEMBLIES ARE REMOVED WHEN THE VEHICLE IS MOVING. THE VEHICLE MUST BE AT A COMPLETE STOP TO ENGAGE THE "AWD" FEATURE.

4. With the vehicle at a complete stop, engage the "AWD" feature by depressing the "AWD" switch to the "ON" position. Allow the vehicle to slowly roll forward for about 10 yards to make sure the "AWD" system is engaged.

5. Proceed to road test the vehicle. If the "grinding" noise still exists, proceed to Step 6.

6. Use a stethoscope to listen to the input shaft bearing. If the "grinding" noise is present replace the input shaft cone and roller assembly. Refer to the appropriate model year Car Shop, Volume E, Section 15-25 for removal and installation details.

7. If the "grinding" is still present after performing Step 6, remove the rear axle cover and check for scored gears, worn bearings, excessive backlash or metal deposits in the rear axle fluid. Service as required.


REAR HALFSHAFT SPLINE GRUNT (1987 ONLY)

A "grunting" noise from the rear of the vehicle that can only be heard from inside the passenger compartment may be due to the rear halfshafts. The "grunting" noise may occur when entering or exiting the vehicle, during braking or driving on rough roads.

1. Remove the rear halfshaft assemblies from the vehicle.

WARNING: DO NOT ENGAGE THE "AWD" FEATURE WHILE THE REAR HALFSHAFT ASSEMBLIES ARE REMOVED WHEN THE VEHICLE IS MOVING. THE VEHICLE MUST BE AT A COMPLETE STOP TO ENGAGE THE "AWD" FEATURE.

2. Road test vehicle in front wheel drive with "AWD" switch in the "OFF" position.

3. If the "grunting" noise is gone, install two (2) new halfshaft assemblies. If the noise is still present, proceed to Step 4.

4. Check for loose items in the luggage compartment, loose suspension fasteners or a loose spare tire. Service as required.