K 10 P/U 4WD L6-292 4.8L (1985)
Vacuum Regulator Valve: Description and Operation
Manual Valve
Establishes range of transmission operation as selected by the vehicle operator through the manual selector lever.
1-2 Regulator Valve
Regulates modulator pressure to a proportional pressure, tending to keep the 1-2 shift valve in downshift position.