45RFE, 545RFE, 65RFE, 66RFE, 68RFE

Line Pressure Booster Kit
Part No. RFE-LB1

Fits gas and diesel units.

View Instructions Find a Distributor

Chrysler RFE transmissions have a unique, full range pressure transducer and real-time adaptive closed-loop pressure control system. Because of this, it is not possible to raise pressure in an RFE the same way you would in other transmissions. The typical method of installing a stronger pressure regulator spring or larger boost valve will not work because the RFE control module will simply adapt and return pressure to OE specification. An electrical booster option is the only way to raise pressure on an RFE.

Sonnax line pressure booster kit RFE-LB1 is an improved design over a simple resistor circuit. Featuring an integrated chip (IC) circuit and a stronger pressure regulator spring, this new kit delivers 10 psi increase at lower pressure range and 25 psi increase at higher pressure ranges. Only Sonnax line pressure booster kits provide progressive pressure increase which gives you smooth engagements and lower load on the pump at idle, but a greater increase in pressure as the transmission is worked harder. To find out more about how the kits work, and what results you can expect, see Achieving a Progressive Pressure Boost in RFEs.

This kit is ideal for heavy duty and modified vehicles and even stock transmissions when a little extra pressure is desired.

  • Achieve shorter shifts and increased torque capacity without creating low-speed harshness
  • Improved clutch holding capacity for increased durability
  • Progressive pressure increase as driving conditions become more demanding
  • One kit fits both gas and diesel applications

This kit is not recommended for use with transmission tuning mods. If you are unsure of the vehicle’s programming, use a scan tool to verify transmission line pressure meets stock levels (Drive at idle = 60 psi, Drive under heavy load = 160 psi). If desired line pressure values are greater than this, the system most likely has aftermarket tuning mods to the transmission pressure.

  • Pressure Regulator Spring
  • Wiring Harness with Connectors

Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.

Chrysler 45RFE, 545RFE, 65RFE, 66RFE, 68RFE Valve Body Layout

Chrysler 45RFE, 545RFE, 65RFE, 66RFE, 68RFE Valve Body Layout

  • 45RFE, 545RFE, 65RFE, 66RFE, 68RFE Line Pressure Booster Kit RFE-LB1


How to Raise Chrysler RFE Transmission Line Pressure — No Tuning Required
Clean Up Your Shifts with Sonnax Line Pressure Booster Kits

Sonnax Line Pressure Booster Kits

Crisp, clean shifts without harshness

Sonnax booster kit components are uniquely designed for precision pressure control. At low-end pressures, they deliver normal engagements, normal light throttle shifts and smooth coastdown shifts. When vehicles are pushed harder, components progressively increase pressure for improved clutch holding capacity and increased durability.

Learn more about Line Pressure Booster Kits