Excess wear at the accumulator bore or on the critical diameter of the accumulator piston is common in first generation GM 6T70 and 6T75 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 124740-04K 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
• No machining or special tools required