August 21, 2013
GM 6L45, 6L50, 6L80 and 6L90 units often suffer from shift abnormalities caused by excess wear in the actuator feed limit (AFL) bore. This wear prevents proper regulation of oil pressure supplied to control solenoids resulting in harsh or soft shifts, solenoid codes, wrong gear starts, and clutch/band failure. Installing Sonnax actuator feed limit valve kit 104740-47K renews the hydraulic integrity of this circuit, restoring normal shift operation and feel. This drop-in, sleeve/valve assembly provides a new and unworn bore for hydraulic sealing of the valve while the sleeve seals off existing moderate bore wear to prevent fluid loss. A new spring to provide correct limit pressure with the sleeve/valve assembly is also provided.
Proper AFL action depends on correct line pressure supply to the AFL valve. If problems are found with line pressure, Sonnax offers oversized pressure regulator and boost valve kit 104520-07K.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.