Preliminary Checks

Before the rear axle is to be serviced, ensure the source of the problem is the rear axle itself and not from other sources such as noise from the tires, road surface, engine, transmission, wheel bearings, muffler or body parts. Perform the following procedures to check for other sources that could be mistaken for axle noise:
1. Ensure rear axle lubricant is at the correct level and type, then select a level asphalt road to reduce tire and body noise.
2. After vehicle has been driven far enough to warm lubricant, note at which speed the noise occurs then stop vehicle. With vehicle in neutral run engine slowly through the RPM range that the noise occurred to check if noise was caused by the exhaust or power train.
3. Check for tire noise by temporarily inflating all tires to approximately 50 psi for test purposes only. Drive vehicle on a level asphalt road and note if a change in noise occurs compared to noise while tires are inflated at normal pressure. After test is completed, ensure tires are inflated to manufacturer's specification.
4. Check the front and rear wheel bearings by lightly applying the brakes while keeping vehicle speed steady. If the noise diminishes, inspect front and rear wheel bearings by jacking up the front wheels, then spinning or shaking them to determine if bearings are loose. Replace if necessary.
5. With vehicle jacked up, check for metal to metal contact between the spring and the spring opening in the frame, upper and lower control arm bushings and frame and axle housing brackets. Ensure there is no metal to metal contact between the floor of the body and the frame. Replace bushings or rubber insulators if necessary.