Where's Might That Noise Be Coming From?

by Ernest Perez

The engine and the exhaust system are often the first vehicle components that come to mind when you think of the possible sources of noise in your vehicle. However, this noise may not necessarily be coming from either of the mentioned components.  

Certain components of an automobile are often overlooked in the search for sources of noise. This article discusses two places you might want to look the next time you hear strange noises coming from your vehicle.

The Tyres

Not many motorists will think of their tyres when looking for sources of automobile noise. This might be because tyres don't have as many moving parts as the vehicle's engine.

Defective tyres will often produce excess noise. For example, delamination and uneven wear on tyre treads often expose steel belts embedded within the tyre's structure. As the tyre rotates, a brief noise is produced whenever the exposed belts get into contact with the road surface (the kind of noise that would be produced if you dragged a thin wire across your driveway). The physical condition of your tyre's treads might explain why your vehicle is noisy.

Tyres treads often wear unevenly when the wheels are misaligned. Delamination often occurs when you drive around with underinflated tyres for a long period of time.

The Differential

The differential is a relatively small mechanical device that makes it safer for you to make corners. True to its name, this device "supplies" different quantities of torque to your tyres so that the tyres rotate at different speeds. This is important because tyres that travel along the outer section of a corner have to cover a greater distance than those traveling along the inner section. The "outer" tyres therefore need to rotate faster than the "inner" tyres to compensate for the extra distance.

The differential in a rear-wheeled vehicle will often have an independent housing while that in a front-wheeled vehicle is often located within the housing of the transmission system. The "front-wheeled differential" uses the vehicle's transmission fluid for lubrication, while the "rear-wheeled differential" uses its own fluid (differential fluid).

A faulty differential often produces different types of noise (e.g. whistle-like noises, rumbles and cranks) that come from the rear end of your vehicle. Such noises are often an indication that the gears within the differential are worn out/damaged. It might also be an indication that the differential isn't properly lubricated, possibly due to a significant drop in the level of transmission/differential fluid.