Symptoms:

  • Coastdown Neutral
  • Downshift bind-ups
  • Harsh downshifts
  • Flare shifts
  • Pressure control out-of-range codes

Cause:

Excess wear at clutch A or E control bore allows critical pressure loss that prevents proper clutch action.

Correction:

The Sonnax oversized valve corrects circuit pressure loss and restores control timing of the clutch control valves.

ZF6HP21, ZF6HP28, ZF6HP34

Oversized Clutch A & Clutch E Control Valve Kit
Part No. 95740-72K

This kit fits either clutch A or E control bore locations in E-shift versions of ZF6HP21/28/34 (Generation 2) valve bodies only.


You need this if... View Instructions Find a Distributor

Flare upshifts or downshift bind-ups are common problems in vehicles equipped with ZF6HP21/28/34 (Generation 2) transmissions. These problems can be accompanied by a coastdown neutral condition or pressure control out-of-range codes. The clutch control valves control clutch apply and release timing, and problems occur when the clutch control valves wear. Sonnax offers the oversized clutch A and clutch E control valve kit 95740-72K (E-shift version) to restore shift timing and vehicle drivability.

  • Valves are hardcoat anodized to reduce wear
  • Sleeve is made from highly wear-resistant aluminum
  • O-ringed end plug improves sealing

Kit is NOT compatible with ZF6HP19/26/32 (Gen.1) units. To differentiate between Gen. 1 and Gen. 2 valve bodies, see ZF Identification Guide.

  • Clutch Control Valve
  • Boost Valve
  • Boost Sleeve
  • O-Ringed End Plug
  • O-Rings (2) 1 Extra

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.

ZF6HP21/28/34 (Gen. 2) Valve Body Layout

ZF6HP21/28/34 (Gen. 2) Valve Body Layout
  • ZF6HP21, ZF6HP28, ZF6HP34 Oversized Clutch A  & Clutch E Control  Valve Kit 95740-72K

You need this if...

Vacuum tests at the ports indicated fail to hold the recommended minimum in-Hg.

ZF6HP21, ZF6HP28, ZF6HP34 Oversized Clutch A  & Clutch E Control  Valve Kit Vacuum Test Locations