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.
January 21, 2013
June 06, 2018
Brian Wing
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.