February 03, 2022
Vehicles equipped with Chrysler 45RFE, 545RFE, 65RFE, 66RFE and 68RFE transmissions can develop low cooler flow at idle and/or overheated fluid issues after performing aftermarket reprogramming or 'tuning' the PCM/TCM for heavy duty use. Aftermarket programming typically commands a minimum of 100 psi at idle, which the OE pressure regulator cannot provide. This causes the valve to restrict the connection to the converter circuits, resulting in low cooler flow, fluid overheating, and converter crowding that causes stall at idle. Additionally, poor line pressure control can be the result of excessive wear in the pressure regulator valve bore. This wear allows critical oil loss, which can cause lowered line pressure, soft shifting and burnt clutches, or high line pressure and harsh shifts.
Reconditioning the bore and installing Sonnax oversized lube regulated pressure regulator valve kit 44912-15K restores pressure regulator action for line pressure control in all ranges. This valve has an internal check valve that ensures proper converter and lube oil flow under extreme 'tuned' operating conditions, eliminating the fluid overheat and converter related engine stalls at idle. This check valve reseats properly to seal the converter at engine off, eliminating the delayed engagements and converter drainback issues that arise from the outdated technique of drilling a hole in the casting wall between line and lube circuits.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.