December 07, 2016
In Chrysler 845RE and ZF8HP45/55/70 units, the variable force solenoids control clutch apply/release, torque converter clutch apply/release and line pressure. The priming valve ensures proper flow and pressure to the solenoids, which is especially crucial during hot conditions and low pressure. Low solenoid feed pressure at idle can create delayed engagement or wrong gear starts. This priming valve also limits the maximum pressure to all the solenoids. Excessive solenoid feed pressure can flood the solenoids causing gear ratio codes, harsh up/downshifts and excessive line pressure. Installing Sonnax priming valve and seal kit 35740-37K eliminates bore wear and stops leakage for proper solenoid pressure control by incorporating a seal at the critical valve spool associated with bore wear.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.