August 09, 2018
The 2-6 clutches in GM Gen. 2 6T70, 6T75 and 6T80 units are applied in 2nd and 6th Gears in conjunction with other clutch packs. As the 2-6 clutch regulator valve oscillates and strokes over time, bore deterioration results, which prevents proper hydraulic control of the 2-6 clutches. This can cause flares, slipping, erratic clutch apply timing, ratio codes and burnt 2-6 clutches.
Reconditioning the bore and installing Sonnax oversized 2-6 clutch regulator valve kit 124740-66K restores normal shift operation and clutch control by re-establishing the hydraulic integrity of the 2-6 circuit.
Proper operation of 2-6 regulator valve depends on correct AFL pressure being supplied to the pressure control solenoid. If problems are found with AFL pressure, Sonnax offers oversized AFL valve 124740-48K.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.