• 1-2 Quality poor
  • Flare shifts
  • Soft shifts & poor line rise


Wear at the 1-2 accumulator valve and/or bore, allowing loss of torque signal, 1-2 accumulator and/or line pressure.


Refurbish the worn bore and install the Sonnax oversized valve to restore correct hydraulic clearances.


Oversized 1-2 Accumulator Valve
Part No. 84754-57K

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

To help control the 2nd clutch apply pressure and shift feel in the GM 4T65-E, a 1-2 accumulator piston and accumulator valve regulating fluid pressure are used. The 1-2 accumulator valve regulates line pressure using torque signal influence and directs 1-2 accumulator pressure to the spring side of the piston, controlling the 2nd clutch apply. Wear at the bore or valve can allow torque signal, 1-2 accumulator or line pressures to exhaust, resulting in various 1-2 shift complaints.

Sonnax oversized 1-2 accumulator valve 84754-57K is made from wear-resistant, hard-coat anodized aluminum to prevent future wear in a refurbished bore. Annular grooves have been added to the valve spool to hydraulically center the valve in the bore for wear resistance.

  • Valve is hard-coat anodized to prevent wear
  • Can be used in either early- or late-style valve bodies
  • Annular grooves added for hydraulic centering and wear reduction

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.

GM 4T65-E Valve Body Layout

GM 4T65-E Valve Body Layout
  • 4T65-E Oversized 1-2 Accumulator Valve 84754-57K
  • 4T65-E Oversized 1-2 Accumulator Valve 84754-57K

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.

4T65-E Oversized 1-2 Accumulator Valve Vacuum Test Locations