If you’ve ever driven behind a truck here in Pasadena, you’ve probably noticed the big ball in the middle of their rear axle, between the rear wheels. That’s a differential. All rear-wheel drive vehicles have a differential in the back, and most four-wheel drive vehicles have a similar one on the front axle.
The differential is one of those parts that you might have heard of, but not given much thought to. However, as one of the key components of your vehicle’s drivetrain, it arguably performs just as important of a job as any of the parts inside of your engine. All vehicles have at least one differential.
As the name implies, a differential’s job is to compensate for differences – in this case, the difference in wheel speeds when turning. When you turn your vehicle around a corner, your inside wheel has a shorter distance to travel than your outside wheel, meaning that your outside wheel has to turn a little bit faster to match the inside wheel. Your differential is able to accomplish this while still providing power to your wheels. Without a differential, your tires would rub and skip along the road during turns, resulting in audible chirps, especially at low speeds such as during parking.
All of the power that your vehicle’s engine produces has to go through your differentials in order to reach your wheels and propel you forward. They need to be strong enough to handle the stresses they undergo, but also need to be properly lubricated in order to keep their job as easy as possible and minimize wear. Lubrication is provided by differential oil, also known as gear oil, which essentially does the same important job as your engine’s motor oil. This is why you need to get your differential serviced periodically by draining the used, dirty fluid and replacing it with clean fluid that will provide better lubrication.
If your vehicle is front wheel drive, instead of a separate differential, it has a component called a transaxle, which combines both the differential and transmission in one unit. All-wheel drive vehicles also have a differential or transfer case to adjust for speed differences between their front and rear drive wheels.
How can you tell if there is a problem with your differential? The most common symptom of a failing differential is a whine or howl coming from your differential. If the oil is low or too dirty, the lack of lubrication will cause a whine or howl when turning, which may increase in volume with your vehicle’s speed. If you notice this, you should have your differential or transaxle inspected immediately in order to prevent serious damage.
The recommended service interval for differentials varies greatly by vehicle. Front-wheel drive vehicles will need their transaxle to be serviced more frequently than rear-wheel drive vehicles which have a separate differential, so consult your vehicle owner’s manual to find out the schedule for your vehicle.
Where and how you drive will affect how quickly your differential wears as well. If you drive on dirt roads or through rain or snow, you will need differential service much sooner than if you only drive on clean pavement.
If you need help figuring out what to do with your differential or think that it may need service, don’t hesitate to call your Certified Auto Repair Specialist today at (626) 793-2220. CARS is Pasadena’s most trusted vehicle repair shop!