The 545RFE is a five-speed automatic transmission used in Chrysler vehicles. It was introduced in 1998 with the Jeep Grand Cherokee and has also been used in the Dodge Dakota, Chrysler Aspen, and Ram 1500. The 545RFE uses an electronically controlled torque converter clutch (TCC) to improve fuel economy and shift quality. It is equipped with a lockup function that engages the TCC at higher speeds to reduce engine speed and improve fuel economy. The 545RFE is also equipped with a electronic pressure control (EPC) solenoid that regulates line pressure to further improve shift quality.