EVT Mode Low - Engine Running

EVT Mode Low - Engine Running

When the gear selector lever is moved to the Drive (D) position from the Neutral (N) position, the following changes occur in the transmission's hydraulic and electrical systems in order to start the vehicle moving from a stopped position.

Variable Low and 1-2 Reverse Clutch Applies

Pressure Control (PC) Solenoid 3 Trim

The PC solenoid 3 trim is energized (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 and 4th clutch regulator valve; through orifice 12 to the variable low and 1-2 reverse and 4th clutch boost valve; and to the shift solenoid valve - mode B.

Note: Remember that the function of an orifice is to control the flow rate of fluid and rate of apply or release of a clutch.

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

PCS 3 signal fluid, at the variable low and 1-2 reverse and 4th clutch regulator valve, opposes variable low and 1-2 reverse and 4th clutch regulator valve spring force and VL 12 reverse clutch/4th clutch feedback fluid pressure to regulate line or auxiliary line pressure into the VL 12 reverse clutch/4th clutch feed circuit.

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

PCS 3 signal fluid pressure acts on a differential area of the variable low and 1-2 reverse and 4th clutch boost valve, moving the valve against variable low and 1-2 reverse and 4th clutch boost valve spring force to regulate VL 12 reverse clutch/4th clutch feed fluid into the VL 12 reverse clutch/4th clutch feedback circuit. As PCS 3 signal fluid pressure is increased to a given value, the variable low and 1-2 reverse and 4th clutch boost valve opens the VL 1-2 reverse clutch/4th clutch feedback circuit to exhaust. This results in the variable low and 1-2 reverse and 4th clutch regulator valve moving to the full feed position, sending full VL 12 reverse clutch/4th clutch feed pressure (full line pressure) to the variable low and 1-2 reverse clutch.

Shift Solenoid Valve - Mode B

VL 12 reverse clutch/4th 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.

Shift Accumulation

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.

EVT Mode Low - Engine Running