* Wheel bearings: This is a very common cause of grinding noises. A failing wheel bearing will make a grinding or growling sound that often increases with speed. You might also feel a vibration in the steering wheel or floor.
* Transmission: Grinding noises from the transmission usually correlate to gear changes or specific speeds. This indicates potential problems with the gears, bearings, or synchronizers within the transmission itself – a serious and potentially expensive issue.
* Brakes: While squealing is more common, worn brake pads or rotors can sometimes produce a grinding sound, especially if metal-on-metal contact is occurring.
* Differential: The differential (located in the rear axle on rear-wheel-drive vehicles, and in the transmission on front-wheel-drive vehicles like the Alero) can create a grinding noise if the gears are worn or damaged.
* Exhaust system: A loose or damaged exhaust component can create a grinding or scraping sound, particularly if it's rubbing against the undercarriage.
* Drive axles (CV joints): These are common on front-wheel-drive vehicles like the Alero. A failing CV joint will often make a clicking or grinding noise, especially when turning.
To help diagnose the problem:
1. Check the obvious: Inspect the brakes, tires, and exhaust system for any visible damage or looseness.
2. Listen carefully: Try to pinpoint where the noise is coming from. Is it coming from the front, rear, or underneath the car? Does it change with speed or when turning?
3. Test drive: Drive the car slowly and gradually increase speed, listening carefully for changes in the noise. Pay attention to whether the noise is worse during acceleration, deceleration, or while turning.
4. Jack up the car (safely): With the car securely supported on jack stands (never work under a car supported only by a jack), check the wheel bearings for play. Try to rotate each wheel and feel for any roughness or excessive play. Inspect the brakes for wear.
It's crucial to have this investigated by a mechanic ASAP. Ignoring a grinding noise can lead to more serious and costly repairs. Driving with a failing wheel bearing, for example, could cause a complete wheel failure, leading to an accident. A failing transmission could leave you stranded.
