What Is a Differential and Do You Have One?

To better understand what a differential does, think about our local Tucson high school track. There are lanes marked off on the track. For the longer distance races, the starting lines are staggered. The starting lines for the outside lanes are ahead of the starting lines for the inside lanes. That’s to compensate for the longer length of the outside lanes. Staggering the starting lines means that each runner has the same distance to run.

The differential compensates for the difference in speeds between the inside wheel and the outside wheel in a turn, because they have to travel together through slightly different distances.

That’s a lot of work and requires very heavy duty parts. And those parts need protection. The differential fluid lubricates the gears in the differential and keeps them cool.

The fluid eventually gets dirty and worn down. Some kinds of differentials require special additives that break down over time. So vehicle manufacturers recommend intervals for replacing your differential fluid.