Servicing your car's automatic transmission regularly can dramatically extend it's life.

That's because the oil -- or ATF -- does more than just lubricate: It also helps drive the transmission. Damage to the fluid, such as oxidation and shear, will reduce it's holding power. This allows the transmission to slip and overheat, and quickly cause it to fail.

A complete fluid exchange service, performed annually, can add years to your transmission's life.

During normal driving, the transmission gets hot just like the engine. To cool the transmission, the fluid is directed through a cooler that sits inside the radiator.

When the engine cooling system is working properly, the engine coolant passes over the transmission cooler in the radiator. This allows the heat from the transmission to transfer to the coolant, and then be carried away to the outside air.

But if the engine coolant level is low, the coolant won't immerse the transmission cooler properly. So the cooler won't release the heat necessary for the transmission to cool off.