What Is A Differential On A Car?

Like most components of a vehicle, each one has a specific task that helps keep the vehicle moving, turning, or generally functioning. You may have heard of a vehicle differential but what is it and what does it do?

What is a Differential?

As part of the front and/or rear axle assembly, the differential plays an integral role in how your car makes turns. The differential is designed to drive a pair of wheels while allowing them to rotate at different speeds, providing proportional RPMs between the left and right wheels. If the inside tire rotates 15 RPM less in a turn than going straight, then, the outside tire will rotate 15 RPM more than going straight. 

For example, when your vehicle goes around a corner, the wheel on the outside must travel faster than the wheel on the inside. The differential distributes equal amounts of torque to both wheels. This permits the wheels to react to resistance, or provide traction, to give the wheel more resistance to rotate less. The wheel with less resistance rotates faster.

Some vehicles, such as go-karts, are not equipped with a differential. In this case, both driving wheels are forced to rotate at the same speed, usually on a common axle driven by a simple chain-drive apparatus. Front wheel drive vehicles are designed differently in that the axle and differential assembly is located in the transmission axle assembly or transaxle.

3 Types of Differentials

Open Differential is the oldest and most common design that is suitable for various makes and models of vehicles. It’s the most simple, reliable, and widely-used type of differential. The powered pinion gear, located at the end of the driveshaft, engages with the ring gear, which then transmits power to both axles through another set of gears. The only flaw in its design is that when one wheel begins to slip, all power is in essence sent to the wheel with the least traction, making this setup unfit for rock climbing or high-speed racing.

Limited-Slip is similar to an Open Differential but utilizes an integrated clutch system. The clutch mechanism locks the left and right sides of the axle together when a wheel loses traction. This is the preferred system for high performance vehicles such as drag racers and those towing heavy loads.

Torque-Vectoring is the latest and greatest in differential technology. Torque vectoring encompasses a complicated collection of sensors and electronics to obtain data from the steering system, throttle position, road surface, and more, giving it the ability to distribute power to each wheel, according to the data. This option provides maximum traction while cornering, increasing performance significantly.

Caring for the Differential

Regular maintenance on any vehicle is a necessity from oil changes, belts, hoses, and other fluids. The  differential fluid is no exception. Differential oil is used to lubricate manual transmissions and differentials. It’s similar to the importance of engine oil for the engine. It plays a vital role in protecting the differential and transmission, allowing them to function safely and smoothly.

Spent differential fluid becomes dirty and contaminated after time. Continuing to drive with contaminated fluid is risky as it can put unnecessary wear on components, leading to permanent damage. Signs your differential needs service:

    • Whirring noise only when decelerating.
    • A howl or whine during acceleration over small or large speeds.
    • Rumbling or whirring at speeds over 20 MPH but changes while turning.
    • Regular clunking sound every few feet or when starting to move.
    • Steady vibration that increases with vehicle speed.

Plan to have your differential fluid also known as gear oil, or oil in the transaxles changed every 30,000 miles not to exceed 60,000 miles by a trained technician. Clean, fresh oil allows for better protection of the differential leading to a safer ride. As with any component of the vehicle, well lubricated parts equal optimal performance. 

Your car or truck wouldn’t be able to go far without the ability to turn. Lubricating fluid within the differential transfers heat away from gears extending its life and keeping you on the road. For any maintenance service including oil changes, brake flushes, or differential services, turn to Sun Auto Service! We are the experts for complete auto repair and maintenance. Our ASE Certified Technicians have specialized training in all aspects of auto care for all makes and models of cars and light trucks. We have an A+ rating with the Better Business Bureau and it’s easy to see why. We guarantee our work in writing and only perform services you authorize. Why go to the dealer when Sun Auto Service is the number one alternative? Schedule an appointment for your next maintenance service and see what makes Sun Auto Service the best choice in automotive care.