May 25, 2017
GM 6T40 third generation transmissions may exhibit multiple line pressure and converter-related problems due to excess wear in the main pressure regulator bore. Wear at the inboard end allows PCS (pressure control solenoid) fluid to cross leak into converter feed or vise-versa resulting in multiple shift related concerns. Wear at the narrow spool separating line pressure and suction can result in low line pressure, burnt clutches, and shift complaints. Installing Sonnax drop-in pressure regulator valve kit 144510-17K restores proper line pressure control for renewed shift feel and performance. The valve has lengthened spool diameters to operate in unworn sections of the pump bore and adds valve stability to prevent future wear.
The Sonnax valve kit is designed as a quick and inexpensive repair for pumps showing moderate signs of wear or as a preventative measure to extend the life of the pump.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.