January 14, 2014
Symptoms:
- Inconsistent shift quality
Cause:
Valves, springs and pressurized fluid repeatedly push on the end plugs, causing the plugs to deform and wear. As a result, critical pressure is lost due to excessive clearance between the plug and bore.Correction:
Sonnax drop-in O-ringed end plugs restore correct circuit pressures. The O-ring provides additional sealing to reduce pressure losses past the end plug.ZF6HP21, ZF6HP28, ZF6HP34
O-Ringed End Plug Kit
Part No. 95740-27K
You need this if...
View Instructions
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Valves, springs and pressurized fluid repeatedly push on end plugs causing them to deform and wear. As a result, critical pressure is lost due to excessive clearance betweeen the plug and bore. Sonnax O-ringed end plug kit 95740-27K services the eight individual bores in the ZF6HP21/28/34 (Gen. 2) valve body which use internal end plugs to isolate valves from solenoids. The O-ringed end plugs replace damaged OE end plugs and restore pressure containment to the valve bore.
Also available for this unit is the double O-ringed end plug kit 95740-30K that services all seven of the 12mm dia. bores.
- Prevents loss of critical pressure
- Requires no machining or special tools
- Services all seven bores to isolate valve from solenoids with 12mm internal end plugs
- Drop-in Zip Valve™ parts install quickly and easily
| ID | Valve Location | Dia. |
|---|---|---|
| Upper Valve Body | ||
| A | Clutch D1 Brake Regulator | 13mm |
| B | M-Shift = Shift Valve 3 E-Shift = Position Valve |
13mm |
| Lower Valve Body | ||
| C | Clutch A Control Pressure Regulator | 15mm |
| D | Clutch E Control Pressure Regulator | 15mm |
| E | Clutch Cooling | 13mm |
| F | Bypass Clutch Control Regulator | 13mm |
| G | Converter Release Regulator | 13mm |
| H | Lubrication Control | 13mm |
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.
- Large End Plugs (2) 15mm
- Large O-Rings (4) 2 Extra
- Small End Plugs (6) 13mm
- Small O-Rings (9) 3 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
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ZF6HP21/28/34 (Gen. 2) Vacuum Test Guide
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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.
Note: Port configurations may change due to variations of casting channels between M and E shift, as well as make and model. The location that needs checking will be the first port inboard of the end plug.
