enters the 1234 clutch feedback circuit. As PCS 1234 clutch fluid pressure is increased to a given
value, the 1234 clutch boost valve opens the 1234 clutch feedback circuit to exhaust. This results
in the 1234 clutch regulator valve moving to the full feed position sending full 26 CL/1234 CL
feed pressure (full line pressure) to the clutch.
1-2-3-4 Clutch
The 1234 clutch fluid enters the 1234 clutch housing to move the piston against spring force and
compensator feed fluid to apply the 1-2-3-4 clutch plates.
Fig. 208: Drive Range, First Gear Engine Braking
Courtesy of GENERAL MOTORS CORP.
DRIVE RANGE, FIRST GEAR
As the vehicle speed increases, the transmission control module (TCM) receives input signals
from the automatic transmission input and output speed sensors, throttle position sensor and other
vehicle sensors to determine the precise moment to deenergize or "turn off" shift solenoid 1 and
command OFF the normally-high CBR1/C456 pressure control solenoid 3.
LOW & REVERSE CLUTCH RELEASES
2008 Chevrolet Silverado 1500
2008 TRANSMISSION Automatic Transmission - 6L50/6L80/6L90 - Cab & Chassis Sierra, Cab & Chassis Silverado,
Sierra & Silverado