When you drive around a corner in your car, the outside wheels have a slightly longer distance to travel than the inside wheels. Because of this, the outer wheels need to spin at a faster speed to keep pace with the inner wheels. The component that makes this possible is called the differential. The differential essentially allows your wheels to travel at different speeds without binding or hopping while transferring power from the engine. 

If you have a rear-wheel drive vehicle, the differential is on the rear axle; for front-wheel drive vehicles, the differential function is handled by the transaxle. All-wheel drive vehicles have differentials on both axles, as well as a center differential or a transfer case. This allows compensation between the front and the rear axles. 

Why Differential Service is Important

Since all the power of the engine is transferred through the differential(s), they’re very strong and built to last a long time. However, like other components in your vehicle, your differential needs to be serviced in order to perform its best.   

Like engines, differentials use oil to keep the internal gears lubricated and reduce friction that can cause excessive wear or heat. However, differential oil is much thicker than engine oil. It needs to be changed at regular intervals because the oil will become thin and contaminated over time. If the oil isn’t changed, the differential will start to have metal-on-metal contact, which will wear out its gears. 

What’s Involved in a Differential Service?

During a differential service, your technician will drain the old differential fluid and replace it with new fluid. They’ll also inspect the u-joints, which connect your drive shaft to the differential. In some cases, we may recommend servicing these as well. 

The interval for differential service can vary based on your vehicle, its mileage, and your typical driving conditions, but it’s generally around every 40,000 to 60,000 miles. However, if you frequently drive on dirt roads or other dusty conditions, it may need to be changed more frequently. Check your owner’s manual for recommendations on your car, or ask your service advisor. 

Differential Replacement

Although differentials last a long time, they’ll eventually wear out and need to be replaced. A failing differential isn’t something you want to ignore—it can freeze up while you’re driving and cause you to lose control or damage other parts of your vehicle, like the axle, driveshaft, or transmission. Some common signs your differential needs to be repaired or replaced include:

• Excessive engine oil consumption
• Reduce handling around corners 
• Difficulty steering
• Noises like grinding gears, clunking, whining, or howling
• Sidewall or out tire damage
• Vibrations that increase as you speed up

If you’ve noticed any of the above signs or you’re due for a differential service, contact the pros at EuroCar Service. We specialize in all European makes, including BMW, Audi, Land Rover, Mercedes, Mini-Cooper, Saab, Jaguar, Volkswagen, Volvo, Smart Car, and Fiat! Call us today at (206) 527-8828 or request an appointment online. 

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