Clutch C Engaged

Pressure control solenoid valve 4 is switched OFF causing the fluid level to be high. Line pressure is directed to the safety valve, the clutch valve D, and the holding valve D. Clutch valve C and holding valve C engage when the pressure flows through the safety valve.

Fig 1: Drive Range Schematic - Fourth Gear, Emergency/Substitute Mode

Courtesy of GENERAL MOTORS CORP.