The function of the actuator feed limit (AFL) valve is to provide regulated pressure to shift solenoids. Wear in the AFL bore causes low clutch pressure and results in transmission slips/harsh shifts. This eventually leads to a loss of 4th through 6th Gears, and finally the loss of transmission function.
Installing Sonnax actuator feed limit valve kit 144740-39K renews the hydraulic integrity of this circuit, restoring normal shift operation and feel in all ranges for GM Gen. 1 and Gen. 2 6T30/40/45/50 and 6T35/31/41/46/51 (Gen. 3 6T40) units. 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.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.
Note: Due to the design changes on the Sonnax sleeve and valve, post-install vacuum testing at the inboard port is not a valid sealing test.