As vehicle speed increases and operating conditions become appropriate, the transmission control module (TCM) processes input signals from the automatic transmission input and output speed sensors, the throttle position sensor and other vehicle sensors to determine the precise moment to command ON the normally-low 26 pressure control solenoid and shift the transmission into Second gear. The manual valve remains in the Drive (D) position and line pressure continues to feed the drive fluid circuit.
26 Pressure Control (PC) Solenoid
The 26 PC solenoid is commanded ON, allowing actuator feed limit fluid to enter the PCS 26 clutch fluid circuit. PCS 26 clutch fluid is then routed through orifice #24 to the 2-6 clutch regulator valve.
2-6 Clutch Regulator Valve
PCS 26 clutch fluid, at the 2-6 clutch regulator valve, opposes 2-6 clutch regulator valve spring force and orificed 26 clutch fluid pressure to regulate drive fluid pressure into the 26 clutch circuit. 26 clutch fluid is then routed through orifice #22 to the 2-6 clutch assembly in the transmission case, and through orifice #4 to the spring end of the 2-6 clutch regulator valve.
2-6 Clutch
The 26 clutch fluid from the 2-6 clutch regulator valve is routed through the transmission case to the 2-6 clutch piston assembly. The 26 clutch fluid pressure moves the piston against 2-6 clutch spring force to apply the 2-6 clutch plates.
Accumulator
PCS 26 clutch fluid is also routed to an accumulator valve. The accumulator valve is used to dampen any pressure irregularities occurring in the PCS 26 clutch fluid circuit. This helps to control clutch apply fluid pressure and clutch apply feel.

Drive Range, Second Gear (Gen 1)
Drive Range, Sixth Gear (Gen 1)Windshield Side Garnish Molding Replacement
Windshield Side Garnish Molding Replacement
Callout
Component Name
Preliminary Procedures
Disable the SIR system, if equipped. Refer to SIR Disabling and Enabling.
1
Windshield Side Garnish Moldi ...
Tires and Wheels Description and Operation (Equipment)
GM Recommended Tire Balancer
Hunter RF33 Road Force balancer or equivalent with the following options:
Auto Clamp – allows for centering repeatability and prevent damage to
the wheel.
Wheel Lift – helps prevent wheel damage and assists in the accuracy
of the placeme ...
Turbocharger Wastegate Regulator Solenoid Valve Replacement
Charge Air Bypass Regulator Solenoid Valve Replacement
Callout
Component Name
Preliminary Procedure
Disconnect the radiator outlet hose from the water inlet. Refer to
Water Inlet Replacement.
1
T ...