When you take a corner in your car, the outside wheels have a little bit longer distance to cover than the inside wheels. This means that the outside wheels have to turn slightly faster than the inside wheels. This mechanical magic is made possible by the differential.
The differential is what allows the drive wheels to rotate at different speeds during turns without the wheels sticking or jumping. If your vehicle is a rear-wheel drive, the differential is located on the rear axle. If you’ve noticed a bulge in the middle of the axle when you’re driving behind a truck, that’s the differential.
If your vehicle is a front-wheel drive, the function of the differential is handled by the transaxle. Of course, an all-wheel drive vehicle has a differential on both axles. They also have a center differential or a transfer case between the front and rear axles to compensate for speed differences between the front and rear.
Because all the power of the engine is transferred through the various differentials, you can imagine how strong they need to be and that they’re built to last a long time. That’s why it’s so important to keep your differential properly lubricated. Differential fluid cools and protects the gears.
Your service technician will check the differential fluid level and top it off if necessary. With low fluid, the differential will run too hot and wear prematurely. Ask your service adviser for the recommended time to change your differential fluid. Fresh fluid will extend the life of your differential. Your service technician will also inspect the u-joints, which connect your driveshaft to the differential and he may recommend service. Some u-joints can be lubricated as part of a routine lube, oil and filter change as well.
Now , of course, differentials eventually wear out and need to be replaced. You might notice a strange noise from your axle area as one of the first warning signs. When the differential shows signs of failing, it’s important to repair it quickly. If you leave it too long and it freezes up when you’re driving, you could lose control of your vehicle, as well as cause damage to other parts like the axle, driveshaft or transmission.