Sonnax Chrysler 45RFE/5-45RFE Dodge Durango and Jeep Grand Cherokee Transmission Line Pressure Booster 1999-On 45RFE, 5-45RFE Increases 15-30 PSI The Chrysler 45RFE, 545RFE and 68RFE use a full range line pressure sensor mounted on the outside of the transmission for "closed loop" line pressure control. Due to this system, traditional methods of raising line pressure by changing the PR spring or valves have no effect. Sonnax electronic line pressure booster kits alter the pressure signal sent to the computer, causing the computer to raise line pressure. Sonnax line pressure booster kit 44957-LB1 (68RFE) has 10-15 psi increase, and 44957-LB2 (45RFE, 545RFE) has 15-30 psi increase. Higher line pressure increases clutch holding power and torque capacity, but with these transmissions, the increase has a limited effect on shift feel. Changes in shift feel will be noticed mostly under aggressive driving or loaded conditions. This part is ideal for heavy duty and modified vehicles and even stock transmissions when a little extra pressure is desired. No other modifications are required. The line pressure booster kit installs between the pressure sensor and vehicle harness using OE-style sealed connectors. Simply unplug the vehicle harness and reconnect with one of these parts. Increased line pressure Increased clutch clamping force and torque capacity Installs on outside of transmission Easy plug and play installation