Second Gear

Drive Range, Second 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 de-energize or "turn OFF" the normally low pressure control solenoid 4 trim, to command ON the normally high pressure control solenoid 2 trim, and shift the transmission into Second gear.

1-3 Reverse Clutch Releases

Pressure Control (PC) Solenoid 4 Trim

The PC solenoid 4 trim is commanded OFF, allowing PCS 4 signal fluid to exhaust from the 1-3 reverse clutch regulator valve.

1-3 Reverse Clutch Assembly

13 reverse clutch fluid pressure is exhausted from the transmission fluid pump cover, allowing 1-3 reverse clutch spring force to move the 1-3 reverse clutch piston and release the 1-3 reverse clutch plates.

Shift Solenoid Valve - Mode A

Exhausting 13 reverse clutch fluid pressure passes through the shift solenoid valve - mode A into the 13 reverse clutch/A cooling feed circuit.

#3 Ball Check Valve

13 reverse clutch feedback fluid pressure exhausts into the 13 reverse clutch/A cooling feed circuit, allowing actuator feed limit fluid to seat the ball.

1-3 Reverse Clutch Regulator Valve

1-3 reverse clutch regulator valve spring force moves the 1-3 reverse clutch regulator valve to the released position, allowing 13 reverse clutch/A cooling feed fluid pressure to exhaust.

Variable Hi and 2-3-4 Clutch Applies

Pressure Control (PC) Solenoid 2 Trim

The PC solenoid 2 trim is energized (ON) allowing actuator feed limit fluid to enter the PCS 2 signal circuit. PCS 2 signal fluid is then routed through orifice 20 to the variable hi and 2-3-4 clutch regulator valve.

Variable Hi and 2-3-4 Clutch Regulator Valve

PCS 2 signal fluid, at the variable hi and 2-3-4 clutch regulator valve, opposes variable hi and 2-3-4 clutch regulator valve spring force and VH 234 clutch feedback fluid pressure to regulate line or auxiliary line pressure into the VH 234 clutch/B cooling feed circuit.

Variable and 2-3-4 Clutch Boost Valve

PCS 2 signal fluid pressure acts on a differential area of the variable hi and 2-3-4 clutch boost valve, moving the valve against variable hi and 2-3-4 clutch boost valve spring force to regulate VH 234 clutch/B cooling feed fluid into the VH 234 clutch feedback circuit. As PCS 2 signal fluid pressure is increased to a given value, the variable hi and 2-3-4 clutch boost valve opens the VH 234 clutch feedback circuit to exhaust. This results in the variable hi and 2-3-4 clutch regulator valve moving to the full feed position, sending full VH 234 clutch feed pressure (full line pressure) to the variable hi and 2-3-4 clutch.

Shift Solenoid Valve - Mode A

VH 234 clutch/B cooling feed fluid passes through the shift solenoid valve - mode A into the VH 234 clutch feed fluid circuit and is routed to the shift solenoid valve - mode B.

Shift Solenoid Valve - Mode B

VH 234 clutch feed fluid passes through the shift solenoid valve - mode B into the VH 234 clutch circuit and is routed to the variable hi and 2-3-4 clutch assembly.

Variable Hi and 2-3-4 Clutch Assembly

VH 234 clutch fluid is directed to the variable hi and 2-3-4 clutch piston to apply the variable hi and 2-3-4 clutch plates and achieve Second gear.

Shift Accumulation

1-3 Reverse Clutch Accumulator

13 reverse clutch fluid also exhausts from the 1-3 reverse clutch accumulator assembly. Accumulator spring force moves the 1-3 reverse clutch accumulator piston to the released position.

Variable Hi and 2-3-4 Clutch Accumulator

VH 234 clutch fluid is also sent to the variable hi and 2-3-4 clutch accumulator assembly. VH 234 clutch fluid moves the variable hi and 2-3-4 clutch accumulator piston against accumulator spring force to cushion the apply of the variable hi and 2-3-4 clutch assembly.

Fluid Pressure Directed in Preparation for a Shift to Third Gear

Shift Solenoid Valve - Mode B

VH 234 clutch/B cooling feed fluid is routed to the shift solenoid valve - mode B where it is blocked by the valve in preparation for an upshift to third gear.

Drive Range, Second Gear