Tool Required VB-FIX Required
- D1 Brake burned
- Harsh Reverse
- Reverse slip
Shift valve 3 uses Reverse fluid pressure to regulate line pressure into the D1 brake control circuit. Bore wear caused by valve oscillation can lead to loss of critical Reverse and line pressure and diminish D1 brake control pressure.
The oversized Sonnax shift valve 3 allows the bore to be refurbished to restore proper hydraulic clearances, eliminating valuable fluid pressure loss.
Oversized Shift Valve 3 Kit
- End Plug
- O-Rings (2) 1 Extra
This kit fits M-shift versions of ZF6HP21/28/34 (Generation 2) valve bodies only.
Harsh reverse engagement, slippage in reverse or a burned D1 brake can indicate a worn shift valve 3 in vehicles equipped with ZF6HP21/28/34 (Gen. 2) units. In Reverse, the valve uses reverse pressure to regulate line pressure into the D1 brake control circuit. The valve moves under the combined influence of the spring and orificed reverse pressure inboard, which are opposed by reverse pressure outboard. Wear at the inboard spool can reduce apply pressure, causing the D1 brake to slip and burn. Outboard wear lessens the valve's ability to regulate line pressure leading to a harsh D1 apply. Sonnax oversized shift valve 3 kit 95740-74K allows the worn bore to be refurbished, restoring proper hydraulic clearances and eliminating loss of valuable line, reverse and D1 brake control circuit fluid pressures.
- Valve is hardcoat anodized to reduce wear
- Spring reproduces OE function with the oversized valve
- O-Ringed end plug reduces or eliminates end plug leakage
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.
- Required Tool
- Related Part
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- Related Tech Resources
- Valve Body Layout
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Vacuum tests at the ports indicated fail to hold the recommended minimum in-Hg.
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Valve Body Layouts
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