Most drivers have heard of a differential—but what does it actually do? When making a turn in your vehicle, the outer wheels travel faster and further than the inner wheels. The differential is a specialized gearbox that transfers power from the engine to the wheels, while also allowing the wheels to rotate at different speeds around turns.

If you didn’t have a differential, both of the wheels would revolve at the same speed; this means they would travel the same distance as each other and would have a tendency to go in a straight line—like a Hot Wheels car. The tires would also skid and hop as you navigate turns, reducing traction and handling.

With front-wheel-drive (FWD) vehicles, the differential can be found alongside the transmission and is called a transaxle; in rear-wheel-drives (RWD), the differential is located between the rear wheels and connects to the transmission by a driveshaft. In contrast, all-wheel-drive (AWD) and four-wheel-drive (4WD) vehicles have a center differential or transfer case that distributes power to the front and rear wheels. Regardless of the type of differential you have, they work fairly similarly.  

The Importance of Differential Servicing

The gears inside the differential are lubricated by differential oil, which is typically much thicker than motor or transmission oil. In many vehicles, the gear oil gets distributed to the outer wheel bearings only by the splash effect of the spinning gear set, so it’s important to have it checked at every oil change. When the gear oil gets low, it can cause expensive damage to the gear sets and bearings.

Unlike the engine, the differential doesn’t have a filter to remove metal particles or other impurities. Instead, most differentials use a magnet to capture metal shavings. Since differential fluid breaks down over time, it’s critical to service your differential to prevent breakdowns and repairs. Although it can vary based on your make and model, most differential service intervals are at or over 60,000 miles. You can find your manufacturer’s recommendations in your owner’s manual, or we’d be happy to look it up for you.

Signs of a Damaged Differential

In addition to servicing, differentials can experience a variety of issues; fortunately, many of these issues are easy to spot. If your differential needs repair, it’s important to address it in a timely manner. Not only can differential problems quickly snowball and create a more expensive repair, but a compromised differential can make it difficult to turn a corner or cause your wheels to lock up. This could be very dangerous, especially if you’re driving in traffic or at high speeds.

Here are some common signs to watch for:

• Your vehicle makes a rumbling or whirring noise when traveling faster than 20 MPH
• You hear a howling noise while decelerating
• Loud clicking or clunking noises when your car is in motion, especially when turning a corner
• Your car excessively vibrates or shakes, becoming more noticeable as you increase speed
• Difficulty steering through a corner

If you’ve noticed any of the above, or it’s time for your differential service, visit Accurate Automotive Attention! Family-owned and operated since 1969, we’re Yuma’s only AAA-Approved auto repair facility and have been voted Yuma’s Best Auto Repair for 20 years in a row. We have two locations to serve you in Central Yuma and the Foothills. Contact us today or request an appointment online!

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