Star Auto Service & AC

The Star Auto Service & AC Guide to Servicing Your Differential

Posted April 26, 2026 1:20 PM

Differential? What's that? And what's it for? I've been told by my service advisor that I need to get it serviced, but is that on the level?

Do these questions sound familiar? They're not uncommon for Brea drivers. A lot of us in Brea don't know what a differential is or what it's for. Every vehicle has a differential, and, yes, it does need to be serviced. In fact, it's more important to the operation of your vehicle than the air conditioner or windshield wipers.

A differential allows your vehicle tires to move at different speeds. This happens more than you think. The best example is when a vehicle is turning. The inside wheel travels a much shorter distance than the outside wheel during a turn. This means the outside wheel has to move faster than the inside wheel. Without a differential, your tires would hop and skip while turning. They would also lose traction in sand or snow.

The location of your differential depends on what kind of vehicle you drive. On a rear-wheel drive vehicle, the differential is located in the back. For a front-wheel drive vehicle, it is located on the front, but it is usually called a transaxle. Four-wheel drive vehicles have three differentials: one on the front, one in the back and one in the middle. This center differential compensates for differences in speed between the front and rear wheels.

Your differential contains strong gears that need to be protected from dirt, debris, water and other contaminants. A differential is sometimes referred to as a “gear box.” The work of these gears is to transfer power from the vehicle drive train to the wheels.

Your differential needs fluid to lubricate and cool the gears. This fluid, even though enclosed in the “gear box,” can get dirty because the gears grind down over time, releasing tiny bits of themselves into the fluid. Also, the additives in the differential fluid break down and need to be replaced. That's why preventive maintenance for your vehicle needs to include servicing the differential.

Your owner's manual can give you recommendations on how often to service your differential. But you should also consult with your friendly and knowledgeable Star Auto Service & AC professional. Star Auto Service & AC can give you some good auto advice on whether your vehicle needs to be serviced more frequently. For example, if you drive in hot or cold CA weather conditions, your differential will need to have its fluid changed more often.

Severe conditions will also affect your vehicle care routine and your differential. Check your owner's manual for a definition of “severe service” conditions that affect your vehicle. Examples may include driving with frequent stops and starts, a lot of short trips around Brea, hot or cold CA weather conditions and towing.

Off-roading is particularly hard on a vehicle's differential. If you are an off-roader, especially if you cross CA streams or waterways, it is important that you service your differential more frequently than the recommendations suggest.

Properly servicing your differential will extend its life and keep you out of Brea auto repair shops. A smooth ride is the result of proper preparation and smart choices.