Excess wear at the accumulator bore or on the critical diameter of the accumulator piston is common in GM Gen. 2 6T70, 6T75 and 6T80 transmissions. The 4-5-6 accumulator piston is utilized during apply of the 4-5-6 clutches to smooth engagement. Wear at this bore allows 4-5-6 clutch apply oil to exhaust, resulting in ratio codes, harsh or delayed application of the clutch pack, burnt clutches and slipping/flares. Installing Sonnax 4-5-6 accumulator piston kit 124740-57K eliminates leaks to restore normal shift operation and feel.

• O-Ring incorporated for positive sealing, even in worn bores
• Annular grooves help center piston in bore to reduce future side-load wear
• Hardcoat anodized aluminum piston combats premature wear
• Drop-in Zip Valve™ parts install quickly and easily