ZF8HP70, 845RE, ZF8HP45, ZF8HP55 Priming Valve and Seal Kit Sonnax Number 35740-37K. ZF valve name: DR-RED-V (DR-V), Chrysler valve name: PR-V.
In Chrysler 845RE and ZF8HP70/45/55 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.
- Hardcoat anodized valve combats premature wear
- Scarf-cut seal on critical valve spool expands to prevent leakage passed any wear
- O-ringed end plug seals critical oil circuit against wear
- Drop-in Zip Valve parts install quickly and easily
- Seal Scarf-cut
- End Plug
- O-Rings (2)
- Harsh shifts
- Neutral shifts
- Gear loss
- Delayed engagement
- Wrong gear starts
- Flare shifts
- Gear ratio & solenoid codes
Bore wear at the priming valve allows pressure escape that causes drivability problems.
Stop pressure loss and restore normal solenoid feed pressures by installing the Sonnax drop-in priming valve and seal kit