What type of transmission fluid should I use?
Automatic transmissions use a special type of oil called automatic transmission fluid, or ATF. This fluid has a number of functions in the transmission, including lubrication, clutch cooling.
The ATF even provides a link between the engine and the transmission through a hydraulic clutch called a torque converter. And, being sandwiched between the clutches, the ATF acts as a "glue", providing additional friction and retaining ability to drive the car.
The easiest way to make sure you are using the right type of ATF is to check the user's guide.