
Hello Valparaiso - let's talk differentials. Brandy here and if you have a rear-wheel drive vehicle, your differential is on the back axle. With front-wheel drive cars, the differential is up front. All-wheel drive and 4-wheel drive vehicles have three differentials - front, rear and in the middle. So you see, you've got a differential (or two or three) and it needs service now and then. Let's get barkin'!!!
What does your vehicle's differential do? Well, it compensates for the speed difference between your outer and inner wheels during a turn. Using the dimensions of a typical car, let's compare the distance the wheels travel from the start of a turn to its completion.
The inside wheel travels about 12.6 feet/3.8 meters. How much farther does the outside wheel travel? About 18.8 feet/5.7 meters – over 6 feet/1.9 meters more. This means the outer tire has to rotate 9 times in the same amount of time that the inner tire rotates only 6 times, so the outer tire has to spin faster to keep up. The differential makes this possible.
The gears in the differential are cooled and lubricated by differential fluid. It's this fluid that needs to be serviced. Small bits of the gears break off and are suspended in the differential fluid. The dirtier the fluid, the faster the gears wear.
So your Automotive care articles and videos technician drains the old fluid out and replaces it with fresh fluid. Some differentials also require a special additive to be added at this time.
So, when should you have your vehicle's differential serviced? Intervals vary from vehicle to vehicle – and may be as short as 15,000 miles/24,000 km – so check your vehicle owner's manual or ask us at Automotive care articles and videos. If you frequently drive with heavy loads, tow a trailer or drive in hot Indiana conditions, you may need to change differential fluid more often. Servicing your differential on schedule at Automotive care articles and videos can save a pricey replacement down the road.

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Automotive care articles and videos
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