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.
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.