Non-Axle Noise
Noise, Vibration and Harshness (NVH)
Noise Diagnostic Procedure
Non-Axle Noise
The five most important sources of non-axle noise are exhaust, tires, roof racks, trim and mouldings, and transmission.
Therefore, make sure that none of the following conditions are the cause of the noise before proceeding with a driveline tear down and diagnosis.
- Under certain conditions, the pitch of the exhaust may sound very much like gear noise. At other times, it can be mistaken for a wheel bearing rumble
- 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. Also, any non-standard tire with an unusual tread construction may emit a roar or whine type noise
- Trim and mouldings can also cause whistling or a whining noise
- Clunk may be a metallic noise heard when the automatic transmission is engaged in reverse or drive, or it may occur when the throttle is applied or released. It is caused by backlash somewhere in the driveline
- Bearing rumble sounds like marbles being tumbled. This condition is usually caused by a damaged wheel bearing