February 12, 2018
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.
Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.