Oil Filter Comparisons

Last Modified : Mar 30, 2021

The automatic transmission is a modern marvel of how hydraulics work. Fluid is pushed through many valves, a filter, a torque converter, and variable rates of pressure to control what they want when they want it. The engine actually spins a part in the torque converter, which in turn pushes fluid against a different part in the torque converter, to actually transfer the power from the engine to the transmission. That's why we don't have to push a clutch! It's other responsibilities include lubricating the gears and clutches and cooling the transmission. So transmissions are what they call transaxles, because they contain a differential assembly as well. That means the fluid also has to lubricate those gears.

That is why the average interval for most vehicles is 30K miles for each fluid change. Some manufactures recommend longer intervals, such as 50K, 60K, or 100K miles changes. There are so many different types of transmission fluids out there, and acceptable use generally has a lot to do with what the manufacturer recommends.

A few hundred dollars every year or two can save you a 4K dollar transmission replacement! Don't forget to service your other drivetrain components, like differentials and transfer cases.