Every Subaru on MT highways has a differential, and it is vital to the proper operation of the vehicle, but most Kalispell auto owners don’t have a clue what it is.

The differential compensates for differing wheel speeds. For example, when you turn, the inside tire on the turn travels a much shorter distance than the outside wheel. So the inside wheel of the Subaru must move at a slower speed than the outside wheel. Without a differential, the wheels would hop and scrape while turning.

Have you ever seen the large bugle-shaped object in the middle of the rear axle of a truck? That’s the differential. In a rear-wheel drive vehicle, the differential is located on the back axle. Four-wheel drive vehicles and SUV’s have differentials on both the front and the rear axle.

You might expect that the differential is located on the front axle of a front-wheel drive vehicle. You’d be right. But the differential is called a transaxle on a front-wheel drive vehicle because its location allows it to be combined with the transmission.

In an all-wheel drive vehicle, an additional differential or transfer case is located between the front and rear axles. Differentials are strong: They have to be because of the vital job they do. But those tough parts need proper lubrication. You don’t want your differential to seize up. That results in expensive damage to your Subaru.

So you need to have your Subaru differential serviced regularly. It’s not a complicated job. At Loren's Auto Repair in Kalispell we've been servicing differentials for 27 years. The used lubricating fluid is simply drained and then replaced. Some vehicles require specific additives in the differential fluid; your Kalispell service center will ensure you are getting what your Subaru needs.

The intervals in time or mileage for servicing your differential vary greatly from vehicle to vehicle. Check with your owner’s manual or Loren's Auto Repair to find out how often your Subaru differential needs to be serviced.

Generally, however, front-wheel drive vehicles need their differential serviced more often than rear-wheel drive vehicles. Also, if you spend a lot of time off-road or on Kalispell area dirt or gravel roads, or if you drive through water, you will need to service your differential more often than the standard recommendation – check with your professional and courteous Loren's Auto Repair service advisor.

Preventive maintenance for your differential is good car care that can spare you costly repair bills. Knowing what your differential is and how it operates is important and will help you understand why this is good auto advice. Remember, take care of your Subaru, and it will take care of you.

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

Do these questions sound familiar? They’re not uncommon for Kalispell drivers. A lot of us in Kalispell 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 critical to the operation of your Subaru than the air conditioner or windshield wipers.

A differential allows your Subaru 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 Subaru 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 vital preventive maintenance for your Subaru 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 professional and courteous Loren's Auto Repair tech. Loren's Auto Repair 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 Kalispell weather conditions, your differential will need to have its fluid changed more often.

Severe conditions will also affect your car 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 Kalispell, hot or cold MT weather conditions, and towing.

Off-roading is particularly hard on a vehicle’s differential. If you are an off-roader, especially if you cross MT 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 Kalispell auto repair shops. A smooth ride for Kalispell auto owners is the result of proper preparation and smart choices.