- 3-4 Concerns
- Soft shifts & poor line rise
Wear at the 3-4 accumulator valve and/or bore, allowing loss of torque signal, 3-4 accumulator and/or line pressure.
Refurbish the worn bore and install the Sonnax oversized valve to restore correct hydraulic clearances and shift control.
Oversized 3-4 Accumulator Valve Kit
To help control the 4th clutch apply pressure and shift feel, a 3-4 accumulator piston and an accumulator valve regulatingfluid pressure are used. The 3-4 accumulator valve regulates line pressure using torque signal influence, and directs 3-4 accumulator pressure to the spring side of the piston, controlling the 4th clutch apply. Wear at the bore or valve can allow torque signal, 3-4 accumulator or line pressures to exhaust, resulting in various 3-4 shift complaints. The oversized Sonnax valves 84754-55K and 84754-58K are made from wear-resistant, hardcoat anodized aluminum to prevent wear in the refurbished bore. The spool lengths have been lengthened significantly for better hydraulic sealing and stability. Annular grooves have been added to hydraulically center the valves in the bore for wear reduction. Two valve designs exist: one for GM models and one for Volvo models.
- Hard-coat anodized valve prevents wear.
- Lengthened valve spool for better hydraulic sealing and stability.
- Annular grooves hydraulically center the valve to reduce wear.
- One tool kit services both GM and Volvo applications.
You need this if...
A vacuum test at torque signal, exhaust or balance ports indicated fails to hold 18" of vacuum or higher, or if visual wear is detected at these ports.
Click here to view PDF if instructions do not appear below.
Valve Body Layouts
Related Tech Articles