Since the front-wheel drive is so common these days, the differential is taken care of during a routine transmission service, so most people don’t even ever have to think about it. And also, most rear-wheel drive differentials don’t have to be serviced for several miles, so, understandably, this is not a service that is on the top of your mind. So if you are one of the many people that either didn’t know you had a differential or didn’t know it needed to be serviced, you are not alone!
To better understand what a differential does, think about a high school track. There are lanes marked on the track to keep runners in their lane. For the longer-distance races, the lines are staggered. The starting lines for the outside lanes are ahead of the inside lanes. This is to compensate for the longer length of the outside lanes, due to the circumference. Staggering the lines allows for each runner to have the same distance to run.
The differential compensates for the difference in speeds on the drive wheels between the inside wheel and the outside wheel in a turn. They have to travel together, but they are traveling slightly different distances.
Differentials do a large amount of work and require very heavy-duty parts. And those parts must be protected. The differential fluid lubricates the gears and keeps them cool. But eventually, the fluid gets dirty and requires replacing. Some kinds of differentials require special additives that break down over time. That’s why manufacturers recommend replacing this fluid.
So what will happen at your NAPA AutoCare Center? Your technician will drain the used fluid and check to see if there are any metal bits. If there are, this could be a sign of excessive wear on the gears. He will then replace the additives, if necessary.
Four-wheel drive vehicles will need special attention because they have differentials on both the front and rear axles that work at different times and sometimes under heavy loads, so they need to be serviced at different intervals.
Check your owner’s manual for the recommended maintenance on your car’s differential today!