Chevrolet Sonic Repair Manual: Drive Range, First Gear (Gen 1)
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 ?urn OFF?the shift solenoid, and to command OFF the normally-high R1/456 pressure control solenoid 3.
- Low & Reverse Clutch Releases
-
Shift Solenoid
The shift solenoid is ?ommanded OFF?allowing shift solenoid fluid pressure to exhaust from the clutch select 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 where it exhausts. 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 R1/456 clutch regulator valve, the 35 reverse clutch regulator valve, and the TCC regulator 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.
- Fluid Pressure Directed in Preparation for a Shift
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R1/456 Pressure Control (PC) Solenoid 3
The R1/456 PC solenoid 3 is commanded OFF allowing PCS R1/456 clutch fluid to exhaust from the R1/456 clutch regulator valve.
R1/456 Clutch Regulator Valve
R1/456 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 PS4 fluid circuit. PS4 fluid is then routed to the normally-closed #4 pressure switch and opens the switch. PS4 fluid is also routed to the #1 ball check valve and flows into the CSV2 latch fluid circuit.
#1 Ball Check Valve
PS4 fluid pressure seats the #1 ball check valve against the 456 clutch fluid circuit. PS4 fluid is then directed into the CSV2 latch circuit and routed to the clutch select valve. CSV2 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 through orifice #25 to the 35 Reverse clutch regulator valve.
3-5-Reverse Clutch Regulator Valve
35 reverse clutch feed/drive 1-6 fluid passes through the 3- 5-reverse clutch regulator valve into the PS3 fluid circuit. PS3 fluid is then routed to the normally-closed #3 pressure switch and opens the switch.
- Fluid Pressure Directed in Preparation for Torque Converter Clutch (TCC) Apply
-
TCC Regulator Apply Valve
Drive 1-6 fluid is routed to the TCC regulator apply valve in preparation for TCC apply.
- Drive Range, First Gear
release blow-off fluid pressures suction converter lube line pcs line solenoid actuator compensatdr low reverse clutch solenoid n.h in mass: clutch tofioue converter assemblv cooler pcs pcs tdc pcs 26 cl ompensator feed regulator valve sel cv valve
Drive Range, Fifth Gear Default (Gen 2)
If the transmission encounters an electrical component malfunction, the transmission
will default to Fourth gear. All solenoids will default to their normal state. If
the torque converter clutch i ...
Drive Range, First Gear (Gen 2)
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 vehi ...
Other materials:
Checking Coolant
The vehicle must be on a level surface when checking the coolant level.
It is normal to see coolant moving in the upper coolant hose return line when
the engine is running.
Check to see if coolant is visible in the coolant surge tank. If the coolant
inside the coolant surge tank is boiling, do ...
Starter Replacement (LUW)
Removal Procedure
Disconnect the negative battery cable. Refer to Battery Negative Cable
Disconnection and Connection.
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
Remove the drivetrain and front suspension frame skid plate. Refer to
Drivet ...
Automatic Transmission Range Selector Lever Replacement
Removal Procedure
Set the park brake and chock the wheels.
Disconnect the transmission range selector lever cable
terminal (1) from the transmission manual shift lever pin.
Press the locking tabs inward in order to release
the transmission range selector lev ...
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