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


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


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. 95740-66K

This kit will fit in either clutch A or E control bore locations in M-shift versions of ZF6HP21/28/34 (Generation 2) valve bodies only. For E-shift versions, Sonnax offers 95740-72K.

You need this if... View Instructions

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 95740-66K (M-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 for better 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 (Generation 2) Valve Body Layout

Zf6hp21 28 34 gen 2

January 14, 2014

ZF6HP19/26/32 (Generation 1), Ford 6R60, 6R75, 6R80, ZF6HP21/28/34 (Generation 2) Identification Guide

Topics: Identification Guides Transmission Ford ZF ZF6HP19 Transmission ZF6HP26 Transmission ZF6HP32 Transmission ZF6HP21 Transmission ZF6HP28 Transmission ZF6HP34 Transmission 6R80 Transmission 6R60 Transmission

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December 21, 2012

ZF6HP21/28/34 (Gen. 2) Vacuum Test Guide

Topics: Vacuum Test Guides Vacuum Testing Transmission ZF ZF6HP21 Transmission ZF6HP28 Transmission ZF6HP34 Transmission

Read Now
  • 95740 66k

You need this if...

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

  • 95740 66k test