Chevrolet Sonic Repair Manual: 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 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.
- Low & Reverse Clutch Releases
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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.
- Fluid Pressure Directed in Preparation for a Shift
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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.
- Fluid Pressure Directed in Preparation for Torque Converter Clutch (TCC) Apply
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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 ?#8201;Gen 2/Hybrid
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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 vehi ...
Drive Range, First Gear Engine Braking (Gen 1)
When the gear selector lever is moved to the Drive (D) range from the Neutral
(N) position, the transmission will provide engine braking. In this operating range,
the normally-low 1234 pressure co ...
Other materials:
Doing Your Own Service Work
Warning
It can be dangerous to work on your vehicle if you do not have the proper
knowledge, service manual, tools, or parts. Always follow owner manual procedures
and consult the service manual for your vehicle before doing any service work.
If doing some of your own service work, use the pro ...
Odor Correction
Eliminating Air Conditioning Odor
Odors may be emitted from the air conditioning system primarily at start
up in hot, humid climates. The following conditions may cause the odor:
Debris is present in the HVAC module.
Microbial growth on the evaporator core
When the blower ...
Engine Coolant Thermostat Housing Installation
Caution: Refer to Engine Coolant Thermostat Housing Caution.
Clean sealing surface.
Install a NEW engine coolant thermostat housing seal.
Install the engine coolant thermostat housing (2).
Caution: Refer to Fastener Caution.
Note: Screw in the 4 ...
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