Symptoms:

  • Delayed engagement
  • Flare shifts
  • Harsh downshifts
  • Neutral shifts
  • High line pressure
  • Harsh upshifts
  • Wrong gear starts
  • Gear ratio & solenoid codes
  • TCC slip

Cause:

All solenoids are fed by the solenoid regulator valve. Worn valve/bore surfaces allow critical pressurized oil to cross leak to the sump, reducing available oil pressure and volume for the solenoids. Shift quality will be adversely affected by wear and operating temperatures.

Correction:

This Sonnax kit eliminates cross leaks and loss of critical oil to the sump, restoring correct oil pressure and volume available to the solenoids.

ZF6HP21, ZF6HP28, ZF6HP34

Oversized Solenoid Pressure Regulator Valve Kit
Part No. 95740-64K

ZF valve name: DR.REO-V


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

In ZF6HP21/28/34 (Generation 2) units, the variable force solenoids control clutch apply/release, torque converter clutch apply/release and line pressure. The solenoid pressure regulator valve insures proper flow volume and pressure to the solenoids during hot conditions and low pressure operation. Low feed pressure at idle can create delayed engagement or wrong gear starts. This 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. Sonnax oversized solenoid pressure regulator valve kit 95740-64K restores proper solenoid function.

• Kit fits either M-shift or E-shift valve bodies

• Valve is hardcoat anodized to reduce wear

• Matching spring reproduces OE function with the oversized valve

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.

F-95740-TL17 can also be used to install ZF6HP21/28/34 (Gen. 1) Sonnax oversized solenoid pressure regulator valve kit 95740-17K.

  • Valve
  • Spring
  • O-Ringed End Plug
  • O-Rings (2)

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 Solenoid Pressure Regulator Valve Kit 95740-64K

You need this if...

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

ZF6HP21, ZF6HP28, ZF6HP34 Oversized Solenoid Pressure Regulator Valve Kit Vacuum Test Locations