Non-Axle Noise

There are other conditions that sound like axle noise and must be considered in diagnosis.

The three most common are exhaust, tires, and trim mouldings.
1. In certain conditions, the pitch of the exhaust can sound very much like gear whine. At other times, it can be mistaken for a wheel bearing rumble.
2. Tires, especially snow tires, can have a high-pitched tread whine or roar similar to gear noise. Radial tires, to some degree, have this characteristic. Any non-standard tire with an unusual tread construction can also emit a roar or whine-type noise.
3. Trim, grille and mouldings can also cause whistling or whining noises.

Make sure that none of these are the cause of the noise before proceeding with axle teardown and diagnosis.