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  • 1-2 Flare
  • 2-3 Flare
  • 2nd Clutch burned (GM)
  • 2nd Slip
  • 3rd Clutch burned
  • 3rd Slip
  • No 2nd
  • No 3rd
  • No 4th
  • Soft & inconsistent shift feel


Excess wear at accumulator piston pin bore allows circuit pressure to escape.


Recover hydraulic control and renew shift feel and performance by reconditioning the pin bore and installing Sonnax oversized accumulator pin.

4T60, 4T60-E

Oversized Accumulator Pin & Reamer Kit
Part No. 84573-02K

Fits 1-2 and 2-3 accumulator locations only

View Instructions

GM 4T60 and 4T60-E units commonly display negative shift characteristics that can be traced to excess wear at the 1-2 and 2-3 accumulator piston pin bores. Slipping, flares, and soft or inconsistent shifts often result, followed by burnt 2nd and 3rd clutches. Extreme cases will cause a loss of 2nd, 3rd and/or 4th gears. Restore hydraulic control and banish sloppy shifting by reconditioning the pin bore and installing Sonnax oversized accumulator pin 84573-02K.

  • Salvages accumulator pistons
  • Oversized pin creates tight hydraulic seal with OE piston
  • Replacement pin kit 84573-01K includes four oversized pins
  • Pins (10)
  • Reamer

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  • 84573 02k combo
  • 84573 02k