November 24, 2015
Vehicles with GM 5L40-E and 5L50-E transmissions are prone to poor line rise or high Reverse pressure problems causing poor shift quality and clutch failure due to leakage at the boost valve assembly. Sonnax offers two boost valve kits: the 55209-01K performance ratio (higher line rise and firmer shifts) and the OE ratio 55209-04K for factory performance.
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.