In GM 8L45 and 8L90 transmissions, the 1-3-5-6-7 accumulator piston is utilized during apply of the 1-3-5-6-7 clutches to smooth engagement. Wear at this bore allows 1-3-5-6-7 clutch apply oil to exhaust resulting in ratio codes, harsh or delayed application of the clutch pack, burnt clutches and slipping/flares. Installing Sonnax 1-3-5-6-7 accumulator piston kit 154740-15K eliminates leaks to restore normal shift operation and feel.

• O-Ring incorporated for positive sealing, even in worn bores
• Hardcoat anodized aluminum piston combats premature wear
• Drop-in Zip Valve™ parts install quickly and easily