February 21, 2013
The OE pressure regulator valve design prevents adequate cooler flow at low RPM and high pressure/demand conditions, which can create overheating. Additionally, in '99-later vehicles, the factory EPC pressure was set high at idle, resulting in engine surge conditions in GM 4L80-E and 4L85-E units. Sonnax lube regulated pressure regulator valve 34200-14K provides a significant increase in cooler flow under low RPM and high-pressure conditions that benefits all vehicles, and eliminates the need for reprogramming '99-later vehicles with high EPC pressure at idle. The replacement pressure regulator valve has an encapsulated check valve that allows regulated flow to the converter charge/lube circuit at vehicle idle.
Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.