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 de-energize or ?urn OFF?the shift solenoid, and to command OFF the normally-high R1/456 pressure control solenoid.
Shift Solenoid
The shift solenoid is commanded OFF allowing shift solenoid fluid pressure to exhaust from the clutch select valve, the default override valve, and the TCC regulator apply valve.
Clutch Select Valve
Shift solenoid fluid is exhausted from the clutch select valve and clutch select valve spring force moves the valve to the released position. This allows R1 fluid pressure to pass through the valve into the exhaust backfill circuit. Drive fluid from the manual valve passes through the clutch select valve and enters the drive 1-6 fluid circuit. Drive 1-6 fluid is routed to the R1/4-5-6 clutch regulator valve, the 3-5-reverse clutch regulator valve, and the TCC regulator apply valve.
Low and Reverse Clutch
Low and reverse clutch spring force moves the low and reverse clutch piston to release the low and reverse clutch plates and force R1 fluid to exhaust from the case assembly. The exhausting R1 fluid is routed to the clutch select valve where it enters the exhaust backfill circuit.
R1/456 Pressure Control (PC) Solenoid
The R1/456 PC solenoid is commanded OFF allowing PCS R1/456 clutch fluid to exhaust from the R1/4-5-6 clutch regulator valve and the R1/4-5-6 clutch boost valve.
R1/4-5-6 Clutch Regulator Valve
R1/4-5-6 clutch regulator valve spring force moves the valve to the released position, allowing R1/456 clutch feed fluid to enter the exhaust backfill circuit, and drive 1-6 fluid to enter the latch fluid circuit. Latch fluid is routed to the #1 ball check valve.
#1 Ball Check Valve
Latch fluid pressure seats the #1 ball check valve against the 456 clutch fluid circuit. Latch fluid is then directed to the clutch select valve. Latch fluid combines with clutch select valve spring force and holds the valve in this position during all six forward gear ranges.
#2 Ball Check Valve
Drive 1-6 fluid pressure seats the #2 ball check valve against the 35 reverse clutch feed fluid passage, and is directed into the 35 reverse clutch feed/drive 1-6 circuit. 35 reverse clutch feed/drive 1-6 fluid is routed to the #3 ball check valve.
#3 Ball Check Valve
35 reverse clutch feed/drive 1-6 fluid pressure unseats the #3 ball check valve and is directed to the 3-5-reverse clutch regulator valve.
TCC Regulator Apply Valve
Drive 1-6 fluid is routed to the TCC regulator apply valve in preparation for TCC apply.
OnStar Description and Operation
This OnStar® system consists of the following components:
Telematics communication interface control module
OnStar® three button assembly
Microphone
Cellular antenna
Navigation antenna
Bluetooth® antenna (If equipped)
Back up battery (If equipped)
This system also interfaces wi ...
Heater Outlet Hose Replacement (LDE, LUW)
Special Tools
BO-38185 Hose Clamp Pliers
For equivalent regional tools, refer to Special Tools.
Removal Procedure
Drain the cooling system. Refer to Cooling System Draining and Filling.
Disengage the heater outlet hose quick connect clip (1) at the heater ...
Timing Belt Center Front Cover Replacement
Timing Belt Center Front Cover Replacement
Callout
Component Name
Preliminary Procedure
Remove the timing belt upper front cover. Refer to Timing Belt Upper
Front Cover Replacement.
Remove the engine mount bracket. Refer ...