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)OnStar Overview
If equipped, this vehicle has a comprehensive, in-vehicle system that can connect
to a live Advisor for Emergency, Security, Navigation, Connection, and Diagnostic
Services.
The OnStar system status light is next to the OnStar buttons. If the status light
is:
Solid Green: System is ...
Hood Ajar Indicator Description and Operation
Hood Ajar Switch
The body control module (BCM) applies B+ to the hood ajar signal circuit
and monitors the voltage to determine the position of the hood. When the hood
is closed, the switch is open and voltage remains high. When the hood is open,
the switch is closed and the voltag ...
Input and Output Speed Sensor Removal
Input and Output Speed Sensor Removal
Callout
Component Name
1
A/Trans Output Speed Sensor Bolt M6 x 18 (Qty: 1)
2
A/Trans Output Speed Sensor Assembly
...