Automatic transmissions transmit engine torque and power to to the rear wheels. Through gear ratios and torque multiplication, the transmission helps to adjust the engine rpm at various speeds. In the highest gear, the transmission is at 1:1 gear ratio, and in overdrive transmissions the final drive ratio is typically 0.75:1 allowing less rpm to accomplish the same vehicle speed. Automatic transmissions use a low viscosity fluid as the power transmission. Automatic transmission fluid (ATF) operates various hydraulic components within the transmission and acts as a lubricant between components to reduce the coefficient of friction (heat) and prevent unusual wear in metallic components. Since this fluid travels throughout the entire transmission, it is easy for damaged components and small metal particles to affect other circuits within the component. A filter, located in the drain pan of the transmission helps to remove these particulates. Improper maintenance or a clogged filter, however, will typically fail and allow contamination throughout the transmission.