Differential Services

All About Differential Services

When it’s time for a routine vehicle inspection at your local Kennedy Transmission branch, we might tell you your vehicle requires differential service. But what exactly is a differential and what does it do? With front-wheel drive vehicles being so common, a standard transmission service usually takes care of the differential; most people don’t even have to think about it. Still, your vehicle’s differential plays a key role when the rubber hits the road. All drivers should know what a differential does and what goes into a standard service.


What is a differential?

If you paid attention during your high school physics (or Driver’s Ed) class, you know that as you turn a car, your outside wheels and inside wheels turn at different speeds. Imagine cars going around an oval race track: cars driving in the outside lanes have further to travel than cars in the inside lanes. To correct this, the differential rotates the outside and inside drive wheels at slightly different speeds. This difference ensures the tires don’t hop or skip while taking corners or lose traction in dirt or snow. Differentials have gears in them that transfer the power from the drive train to the wheels. That’s why they’re often referred to as gearboxes. The gears need to be very strong to handle this work, and they need to be properly protected so they’ll last.


Does my car have a differential?

All vehicles have some form of differential. Here’s a breakdown of the most common types:

  • Front-wheel drive: For FWD vehicles (the most common for consumer cars), the differential sits between the front wheels. This form is called a transaxle because it combines the differential and transmission in one unit.
  • Rear-wheel drive: For RWD vehicles like trucks and commercial vans, the differential sits between the back two wheels. Because the transmission is not in the same location, RWD differentials receive less wear-and-tear during normal driving conditions. They can go longer between servicing.
  • Four-wheel (or all-wheel) drive: These vehicles have differentials in the front, the back, and in the middle. The center differential (often called a transfer case) adjusts for differences in speed between the front and rear wheels.


Why is differential service important?

Most of the vehicles you see on the road, even the smallest ones, weigh between three and six thousand pounds – trucks weigh even more. To get that much weight moving, all of the power from the engine directs down through the transmission, on to the differential, and then out to the drive wheels. That’s a lot of work and requires heavy duty parts. And those parts need protection.

Differential fluid lubricates and cools the gears involved in this process. Over time, this fluid becomes dirty from bits of these gears grinding off. Also, chemical additives (that keep the differential fluid clean and protected) break down over time. Because of all this wear and tear, vehicle manufacturers change the differential fluid at scheduled intervals. Contact your local Kennedy Transmission service advisor if you have questions about your recommended schedule.

If you’re driving under more severe conditions, you’ll want to service your differential more frequently. Most owner’s manuals define “Service Service” conditions as frequent starts and stops, short trips, cold or hot weather, and towing. All these conditions add to the stress of the vehicle and its parts. Proper service will extend the life of your gears and keep them running more smoothly.


Trust the Kennedy Transmission Difference with Your Differential

Differentials are hard-working mechanisms. Along with the gears in a manual transmission, they need to be serviced regularly with high-quality replacement fluid. The expert technicians at Kennedy Transmission can give you more information about when your next differential service is recommended. You can also ask if they have a record of when the service was last completed. Find a location nearest you to schedule an appointment today!

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