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Symptoms:
  • 5-4 Flare
  • 5-4 Neutral
  • Delayed Forward
  • Harsh Forward
  • No 4-5
  • VFS 1/A solenoid control code
Cause:

OE boost sleeve wears prematurely, allowing critical pressure loss and/or seizure of valve within sleeve.

Correction:

Recover hydraulic control and renew shift performance by installing Sonnax clutch A & E control boost valve kit.

ZF6HP21, ZF6HP28, ZF6HP34

Clutch A & E Control Boost Valve Kit

Part No.

95740-28K

Clutch A & E Control Boost Valve Kit
  • 95740-28k_combo

  • Clutch A & E Control Boost Valve Kit

  • 95740-28k_details

Small_95740-28k_combo Small_95740-28k Small_95740-28k_details

ZF6HP21, ZF6HP28, ZF6HP34

Clutch A & E Control Boost Valve Kit

Part No. 95740-28K

  • Valves (2)
  • Sleeves (2)

Sevices 2 bores

Complaint:

  • 5-4 Flare
  • 5-4 Neutral
  • Delayed Forward
  • Harsh Forward
  • No 4-5
  • VFS 1/A solenoid control code

Cause:

OE boost sleeve wears prematurely, allowing critical pressure loss and/or seizure of valve within sleeve.


Correction:

Recover hydraulic control and renew shift performance by installing Sonnax clutch A & E control boost valve kit.

ZF6HP21/28/34 (Generation 2) transmissions are equipped with an aluminum sleeve for the clutch A and E control boost valve. This material is prone to wear from valve plunger reciprocation. Failure of this sleeve results in a variety of shift problems and solenoid codes. The Sonnax clutch A and E control boost valve kit 95740-28K will restore the correct hydraulic clearance and proper function of the assembly.

  • Hardcoat anodized aluminum valve combats premature wear
  • Sleeve is highly wear-resistant to increase service life

NOTE:

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.

Related Parts

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 ZF6HP21/28/34 (Generation 2)
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