Notice: Do not attempt to operate the vehicle without supporting the lower control arm. When the wheel drive shaft CV joints are at a high angle, extra vibrations can occur and may damage the seals and the joints.

Any gear-driven unit produces a certain amount of noise that is normal and cannot be eliminated by conventional repairs or adjustments. Slight noise that is heard only at a certain speed or under unusual or remote conditions is acceptable. For example, a noise that tends to reach a peak at speeds from 60 to 100 km/h (40 to 60 mph) depending on the road conditions, the load conditions, or the tire size, does not indicate trouble in the drive motor assembly.

When a drive motor is suspected of being noisy, inspect in order to determine whether the noise originates from one of the following areas:

Raising the tire pressure in order to eliminate tire noise (although this will not silence tread noise of mud and snow tires), and listening for the noise at varying speeds and road surfaces, on drive, float and coast conditions will help to locate the source of the noise.

Road noise is the result of certain road surfaces, such as brick or rough-surfaced concrete. These surface noises may be mistaken for tire or drive motor noise. Driving on a different type of road, such as smooth asphalt or dirt, will quickly reveal if the road surface is the cause of the noise. Road noise is usually the same in drive or coast. Follow these guidelines when testing for tire or drive motor noise:

Tire noise may be mistaken for drive motor noise. Tire noise, however, changes with different road surfaces. Drive motor noise does not. Test for tire noise, temporarily inflating all tires to 345 kPa (50 psi) pressure. Inflating the tires to this level will only materially alter noise caused by the tires. Inflating the tires to this level will not affect noise caused by the drive motor. Noise usually stops when coasting speeds under 48 km/h (30 mph); however, tire noise will continue with a lower tone as the vehicle speed is reduced.

Follow these guidelines when testing for tire noise:

Wheel bearing noise can be caused by a brinelled wheel bearing causing a knock or click approximately every two revolutions of the wheel, because the bearing rollers do not travel at the same speed as the drive motor and the wheel. With the wheels raised, spin the wheels by hand while listening at the hubs for evidence of a rough or brinelled wheel bearing or loose bearings.

1. Drive the vehicle at a low speed on a smooth road.
2. Drive the vehicle, turning to the left and the right.
3. Raise up the wheel to verify roughness at the wheels.

Gear noise may be categorized into two basic types. The first type is produced by broken, bent or forcibly damaged gear teeth. This type of gear noise is usually audible over the entire speed range and presents no difficulty in diagnosis. For example, hypoid gear tooth scoring generally results form the following:

Hypoid gear tooth scoring will progressively lead to complete erosion of the gear tooth or gear tooth pitting and then eventually fracture if the initial scoring is not corrected. Another cause of hypoid gear fracture is extended overloading of the gear set. This will produce fatigue fracture, or shock loading, resulting in sudden failure.

The second type of gear noise pertains to the mesh pattern of the gear teeth. This form of abnormal gear noise can be recognized because it produces a cycling pitch (whine) and will be very pronounced in the speed range at which it occurs, appearing under either drive, float or coast conditions. Gear noise tends to peak in a narrow speed range or ranges, and will tend to remain constant in pitch. Bearing noise will vary in pitch with vehicle speeds.