What is a differential?
A differential is a critical component of a vehicle’s drivetrain. It is often located on the axle of the vehicle and is responsible for providing power to the wheels. The differential allows the wheels to rotate at different speeds, which is necessary when turning a corner. The number of differentials and also their location depends on the type of vehicle you are looking at. For example, a front-wheel drive vehicle will only have a differential on the front axle. Also, a rear-wheel drive vehicle has a differential on the rear axle. And finally, an all-wheel drive vehicle will have three differentials. The front differential, the rear differential and a differential in the center of the transmission. Some four-wheel-drive systems or part-time full-wheel-drive systems do not have a center differential so that the front and rear wheel spin at the same rate.
The parts that make up a differential
A differential consists of several parts that work together to provide power to the wheels and allow them to rotate at different speeds. These parts include:
- The differential housing is the outer casing that contains the other parts of the differential.
- The differential gears are the gears inside the housing that transmit power from the driveshaft to the axles.
- The drive pinion is the gear that connects the driveshaft to the differential gears.
- The bearings are the bearings that support the differential gears and allow them to rotate smoothly.
A noise from the rear of a vehicle can indicate a differential issue. Differential issues cause a variety of noises, including whining, humming, clunking, and also grinding. If you hear any of these noises, diagnose and then fix the problem as soon as possible to avoid further damage.
The following are some noises you may hear from your differential:
Whining or humming
A high-pitched whine or hum from the rear indicates worn or damaged differential gears. This can happen without sufficient lubrication or with excessive heat or impact. To diagnose the issue, remove the differential cover and inspect the gears for wear and damage. If you see any damaged gears, replace them. Then check the differential for any cracks leading to leaking lubrication.
Clunking or grinding
A clunking or grinding noise from the rear differential indicates worn or damaged differential bearings. This can also be a result of insufficient lubrication or it could be excessive heat or impact. To diagnose the issue, remove the differential cover and inspect the bearings for wear and damage. Replace damaged bearings.
Thumping or knocking
A thumping or knocking noise from the rear indicates a misaligned or damaged differential pinion gear. This can happen with incorrect installation or with excessive heat or impact. To diagnose the issue, remove the differential cover and inspect the pinion gear for misalignment and damage. Replace damaged pinion gear.
Another source of the knocking or thumping noise could come from wear and tear on the axle shafts or the teeth of the gears being broken. These old shafts and gears would need to also be replaced.
How we can help
After diagnosing the problem and determining the cause of the noise, it is important to get the issue repaired as soon as possible. In most cases, this involves replacing worn or damaged parts and properly lubricating the differential.
Working on a vehicle’s differential is complex and dangerous. If you are not experienced with automotive repair, leave the work to a professional mechanic. They have the tools and knowledge to properly diagnose and fix differential issues, ensuring the vehicle is safe and reliable on the road.
Whether you get your differential checked out by a mechanic or not, consider getting your differential repaired by us. Our team of experts has over 75 years of combined experience in repairing, rebuilding and modifying differentials and axles. We can also help you troubleshoot axle problems. We also offer to pick up your differential and ship them back to you with our door-to-door courier service. We are able to offer this service to anyone in the continental United States. Our differentials, rebuilt rear ends, and axle is covered under our warranty.