Third Gear

Drive Range, Third Gear

As vehicle speed increases and operating conditions become appropriate, the transmission control module (TCM) processes input signals from the output speed sensor, the throttle position (TP) sensor and other vehicle sensors to determine the precise moment to command ON the normally low pressure control solenoid 4 trim to regulate 1-3 reverse clutch apply. At the same time the normally high pressure control solenoid 3 trim is commanded OFF, and the transmission shifts into Third gear.

1-3 Reverse Clutch Applies

Pressure Control (PC) Solenoid 4 Trim

The PC solenoid 4 trim is energized (ON) allowing actuator feed limit fluid to enter the PCS 4 signal circuit. PCS 4 signal fluid is then routed through orifice 18 to the 1-3 reverse clutch regulator valve.

Shift Solenoid 2

The shift solenoid 2 is energized, allowing actuator feed limit fluid to enter the solenoid 2 signal fluid circuit. Solenoid 2 signal fluid is routed to the shift solenoid valve - mode A. Solenoid 2 signal fluid is also routed to the variable hi and 2-3-4 clutch regulator valve where it enters the PS3 fluid circuit, and to the 1-3 reverse clutch regulator valve where it enters the PS1 fluid circuit.

1-3 Reverse Clutch Regulator Valve

PCS 4 signal fluid, at the 1-3 reverse clutch regulator valve, opposes 1-3 reverse clutch regulator valve spring force and 13 reverse clutch feedback fluid pressure to regulate line or auxiliary line pressure into the 13 reverse clutch/A cooling feed circuit.

#3 Ball Check Valve

13 reverse clutch feedback fluid unseats the #3 ball check valve, allowing excess pressure to pass into the actuator feed limit circuit. This helps to control clutch apply fluid pressure and clutch apply feel.

Shift Solenoid Valve - Mode A

Solenoid 2 signal fluid is routed to the shift solenoid valve - mode A and moves the valve against shift solenoid valve - mode A spring force to the applied position. This allows 13 reverse clutch/A cooling feed fluid to enter the 13 reverse clutch circuit.

1-3 Reverse Clutch Assembly

13 reverse clutch fluid enters the transmission fluid pump cover and moves the 1-3 reverse clutch piston against spring force to apply the 1-3 reverse clutch plates.

#3 Pressure Switch

Solenoid 2 signal fluid passes through the variable hi and 2-3-4 clutch regulator valve into the PS3 fluid passage. PS3 fluid opens the normally closed #3 pressure switch, signaling the TCM that the transmission is in Drive Range - Third Gear.

#1 Pressure Switch

Solenoid 2 signal fluid passes through the 1-3 reverse clutch regulator valve into the PS1 fluid passage. PS1 fluid opens the normally closed #1 pressure switch, signaling the TCM that the transmission is in Drive Range - Third Gear.

Variable Low and 1-2 Reverse Clutch Releases

Pressure Control (PC) Solenoid 3 Trim

The PC solenoid 3 trim is de-energized (OFF) allowing PCS 3 signal fluid to exhaust from the variable low and 1-2 reverse and 4th clutch regulator valve; the variable low and 1-2 reverse and 4th clutch boost valve; and the shift solenoid valve - mode B.

Variable Low and 1-2 Reverse Clutch Assembly

VL 12 reverse clutch fluid exhausts from the variable low and 1-2 reverse clutch to the shift solenoid valve - mode B allowing the hybrid low, 1-2 clutch to release.

Shift Solenoid Valve - Mode B

VL 12 reverse clutch fluid passes through the shift solenoid valve - mode B and into the VL 12 reverse/4th clutch feed fluid circuit and is routed to the variable low and 1-2 reverse and 4th clutch regulator valve.

Variable Low and 1-2 Reverse and 4th Clutch Boost Valve

Variable low and 1-2 reverse and 4th clutch boost valve spring force moves the variable low and 1-2 reverse and 4th clutch boost valve to the released position, allowing VL 12 reverse/4th clutch feedback fluid pressure to exhaust into the VL 12 reverse/4th clutch feed circuit.

Variable Low and 1-2 Reverse and 4th Clutch Regulator Valve

Variable low and 1-2 reverse and 4th clutch regulator valve spring force moves the variable low and 1-2 reverse and 4th clutch regulator valve to the released position, allowing VL 12 reverse/4th clutch feed fluid pressure to exhaust through the valve into the exhaust backfill circuit.

Transmission Fluid Temperature (TFT) Sensor

Fluid pressure in the exhaust backfill circuit exhausts at the TFT sensor.

#4 Pressure Switch

The applied shift solenoid valve - mode B closes off the PS4 circuit exhaust, allowing fluid pressure in the circuit to build to actuator feed limit fluid pressure. PS4 fluid opens the normally closed #4 pressure switch, signaling the TCM that the transmission is in Drive Range - Third Gear.

#5 Pressure Switch

Actuator feed limit fluid passes through the variable low and 1-2 reverse and 4th clutch regulator valve into the PS5 fluid passage. PS5 fluid opens the normally closed #5 pressure switch, signaling the TCM that the transmission is in Drive Range - Third Gear.

Shift Accumulation

1-3 Reverse Clutch Accumulator

13 reverse clutch fluid is also sent to the 1-3 reverse clutch accumulator assembly. 13 reverse clutch fluid moves the 1-3 reverse clutch accumulator piston against accumulator spring force to cushion the apply of the 1-3 reverse clutch assembly.

Variable Low and 1-2 Reverse Clutch Accumulator

VL 12 reverse clutch fluid also exhausts from the variable low and 1-2 reverse clutch accumulator assembly. Accumulator spring force moves the variable low and 1-2 reverse clutch accumulator piston to the released position.

Drive Range, Third Gear