January 21, 2013
In GM 4L60-E, 4L65-E abd 4L70-E units, wear at the shift valve spools and bore lands causes loss of critical hydraulic pressure which, depending on the wear location and severity, can result in shift timing/feel complaints, 2nd Gear starts, 3rd clutch failure, 3-4 shift complaints and loss of AFL pressure. Reconditioning the bore and installing Sonnax oversized 3-4 shift valve kit 77754-42K restores hydraulic integrity.
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.