Tool Required VB-FIX Required

Printpartsummary
Symptoms:
  • Delayed engagement
  • Flare shifts
  • Gear ratio & solenoid codes
  • Harsh shifts
  • Neutral shifts
  • Wrong gear starts
Cause:

Bore wear at the priming valve allows pressure escape that causes drivability problems.

Correction:

Stop pressure loss and restore normal solenoid feed pressures by reconditioning the bore and installing Sonnax oversized priming valve kit. 

Video Tool Required VB-FIX Required

ZF8HP45, ZF8HP55, ZF8HP70

Oversized Priming Valve Kit

Part No.

35740-21K

Oversized Priming Valve Kit
  • 35740-21k_combo

  • Oversized Priming Valve Kit

Small_35740-21k_combo Small_35740-21k

ZF8HP45, ZF8HP55, ZF8HP70

Oversized Priming Valve Kit

Part No. 35740-21K

  • Valve
  • Spring
  • End plug
  • O-Rings (3) 1 Extra

ZF valve name: DR-RED-V (DR-V)

Chrysler valve name: PR-V

Complaint:

  • Delayed engagement
  • Flare shifts
  • Gear ratio & solenoid codes
  • Harsh shifts
  • Neutral shifts
  • Wrong gear starts

Cause:

Bore wear at the priming valve allows pressure escape that causes drivability problems.


Correction:

Stop pressure loss and restore normal solenoid feed pressures by reconditioning the bore and installing Sonnax oversized priming valve kit. 

The variable force solenoids control clutch apply/release, torque converter clutch apply/release and line pressure. The priming valve insures proper flow and pressure to the solenoids, and 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/down shifts and excessive line pressure. Reconditioning the bore and installing Sonnax oversized priming valve kit 35740-21K eliminates bore wear and stops leakage for proper solenoid pressure control.

  • Hardcoat anodized valve combats premature wear
  • Annular grooves help center the valve in the bore to resist wear

Required Tools

You need this if...

Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.

  • Test Locations

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Valve Body Layouts

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.

Valve Body Layout ZF8HP55
Valve Body Layout ZF8HP45, ZF8HP70
 

Sonnax Webinar Part 1 of 2: Dodge TorqueFlite® 8 (ZF8) Features & 2015 Challenger Test Drive

Watch this webinar recording to learn about:
  • 2015 Dodge Challenger SXT Plus features
  • Test drive in automatic & manual modes
  • Torque converter application strategy & pressure specs
  • Transmission theory of operation and clutch & brake application charts
  • Solenoid & valve body theory of operation & component breakdown

View presentation slides

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