Volt

Reverse Series Mode Engine Off

When the transmission is operating in Reverse - Output Split (R) and the internal combustion engine is OFF, and the HPCM determines that operating conditions are appropriate, Reverse - Series Mode is commanded and the following changes occur in the transmission's hydraulic and electrical systems.

Pressure Control (PC) Solenoid 3

The PC solenoid 3 is energised (ON) allowing actuator feed limit fluid to enter the PCS 3 signal circuit. PCS 3 signal fluid is then routed through orifice #30 to the variable low and 1-2 reverse clutch regulator valve; through orifice #12 to the variable low and 1-2 reverse clutch boost valve; and to the shift solenoid valve - mode B.

Shift Solenoid 1

The shift solenoid 1 is commanded OFF, allowing solenoid 1 signal fluid to exhaust. When solenoid 1 signal fluid exhausts, the shift solenoid valve - mode B moves to the released position.

Variable Low and 1-2 Reverse Clutch Regulator Valve

PCS 3 signal fluid, at the variable low and 1-2 reverse clutch regulator valve, opposes variable low and 1-2 reverse clutch regulator valve spring force and VL 12 reverse clutch feedback fluid pressure to regulate line or auxiliary line pressure into the VL 12 reverse clutch feed circuit.

Variable Low and 1-2 Reverse Clutch Boost Valve

PCS 3 signal fluid pressure acts on a differential area of the variable low and 1-2 reverse clutch boost valve, moving the valve against variable low and 1-2 reverse clutch boost valve spring force to regulate VL 12 reverse clutch feed fluid into the VL 12 reverse clutch feedback circuit. As PCS 3 signal fluid pressure is increased to a given value, the variable low and 1-2 reverse clutch boost valve opens the VL 1-2 reverse clutch feedback circuit to exhaust. This results in the variable low and 1-2 reverse clutch regulator valve moving to the full feed position, sending full VL 12 reverse clutch feed pressure (full line pressure) to the variable low and 1-2 reverse clutch.

Shift Solenoid Valve - Mode B

VL 12 reverse clutch feed fluid is routed to the shift solenoid valve - mode B, where it passes through the valve into the VL 12 reverse clutch circuit.

Variable Low and 1-2 Reverse Clutch Assembly

VL 12 reverse clutch fluid pressure enters the case assembly behind the variable low and 1-2 reverse clutch piston and moves the piston against spring force to apply the variable low and 1-2 reverse clutch plates.

Pressure Control (PC) Solenoid 2

The PC solenoid 2 is commanded OFF, allowing PCS 2 signal fluid to exhaust from the variable hi and 2-3-4 clutch regulator valve and the variable hi and 2-3-4 clutch boost valve.

Variable Hi and 2-3-4 Clutch Assembly

VH 234 clutch fluid pressure is exhausted from the case assembly, allowing variable hi and 2-3-4 clutch spring force to move the variable hi and 2-3-4 clutch piston and release the variable hi and 2-3-4 clutch plates.

Shift Solenoid Valve - Mode B

Exhausting VH 234 clutch fluid pressure passes through the shift solenoid valve - mode B into the 234 clutch feed circuit.

Shift Solenoid Valve - Mode A

Exhausting 234 clutch feed fluid pressure passes through the shift solenoid valve - mode A into the VH 234 clutch/B cooling feed circuit.

Variable Hi and 2-3-4 Clutch Regulator Valve

Variable hi and 2-3-4 clutch regulator valve spring force moves the variable hi and 2-3-4 clutch regulator valve to the released position, allowing VH 234 clutch/B cooling feed fluid pressure to exhaust.

Variable Low and 1-2 Reverse Clutch Accumulator

VL 12 reverse clutch fluid is also sent to the variable low and 1-2 reverse clutch accumulator assembly. VL 12 reverse clutch fluid moves the variable low and 1-2 reverse clutch accumulator piston against accumulator spring force to cushion the apply of the variable low and 1-2 reverse clutch assembly.

Variable Hi and 2-3-4 Clutch Accumulator

VH 234 clutch fluid also exhausts from the variable hi and 2-3-4 clutch accumulator assembly. Accumulator spring force moves the variable hi and 2-3-4 clutch accumulator piston to the released position.