Sonnax 4L80E 4L85E Transmission Lube Regulated Pressure Regulator Valve 34200-14K The OE pressure regulator valve design prevents adequate cooler flow at low RPM and high pressure/demand conditions, which can create overheat complaints. Additionally, in '99-later vehicles, the factory EPC pressure was set high at idle, resulting in engine surge conditions in GM 4L80-E & 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. Replacement pressure regulator valve has an encapsulated check valve that allows regulated flow to the converter charge/lube circuit at vehicle idle Check valve prevents converter or pump drainback Improves converter release pressure Prevents engine surge at idle in'99-later vehicles