Caring for Your Vehicle’s Differential: It’s Not Just about Engine Oil


Do you know what your differential is on your car or SUV? You’ve probably seen it even if you haven’t done anything with it. While you frequently change the oil in your engine, the differential oil is an overlooked task for most non-FWD SUVs, light trucks, and passenger cars. The differential sits at the rear and underneath your car, so it doesn’t get as much love as the engine and front parts of the vehicle. However, if your differential isn’t lubricated, it could fail, and you won’t get far. The good news is you only have to change the oil in the differential every 30,000-50,000 miles. Check your owner’s manual to see when it is recommended.

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What Is the Differential?

Your vehicle’s differential is a component found in all cars, and it’s designed to compensate for differences in the distance your inner and outer wheel travel as you go around curves and turn corners. For rear-wheel-drive cars, the differential uses its own lubrication and housing unit. The lubricant is a thicker, darker oil that usually had 80 weight, making it heavier. Front-wheel-drive vehicles usually house the differential in with the transmission housing, which both share the same fluid. Therefore, when you get any maintenance done for the transmission, it also takes care of the differential.

The oil for the differential lubricates the pinion gears and ring, which transfers power to the wheel axles from the driveshaft. If the car has a limited-slip differential, its job is also to keep all moving parts in the assembly healthy and running smoothly. Changing the differential oil is just as essential as changing the oil in your engine. Metal-to-metal contact isn’t good for any of the moving parts and can wear down the surfaces, creating friction heat. This heat weakens the gears and can lead to failure.

It’s relatively easy to change the differential oil. However, if you don’t feel comfortable doing it yourself, you can have a trusted mechanic do it for you.

Types of Differentials

The differential helps your vehicle take corners without issue. If both of the drive wheels rotated at the same time, they could jump-skitter because your outside tires travel farther and faster than the inside ones. While there are many variations in design, they all fall into three primary categories.

Open

This is the oldest style of differential. The rugged and simple design is used extensively. The pinion gear meshes well with the ring gear, and the ring gear transmits the power to your axles using a second gear set. Of course, there is a caveat of this style: if slippage does occur, the power automatically goes to the wheels with the least grip.

Limited Slip

Because slippage can happen with an open differential, the limited-slip version was born, which is similar to the open differential. A clutch system can be installed on the differential, which helps to overcome the slipping issue. The mechanism can lock the left or ride-side axles together if the wheels start slipping.

Torque-Vectoring

One of the newest options is the torque-vectoring differential. Many people believe that it is the best design possible. It uses all the car sensors to help determine which of the wheels should get the most power. It also uses electronic clutches and controls to ensure that the power gets where it needs to be.

Understanding what the differential is and why it is important can help you understand why you need it. Of course, manufacturers rarely put things on vehicles that aren’t needed, so everything that helps the car run is necessary. However, maintenance is key, and most people never realize that there the differential oil should ever be changed.

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Caring for Your Vehicle’s Differential: It’s Not Just about Engine Oil

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