Power Off High Default

Power Off High Default

If the transmission is in Drive - Output Split during a transmission electrical component malfunction, the transmission will default to High. All solenoids will default to their normal state. The transmission will remain in Power Off - High Default until the ignition has been turned off, or the transmission is shifted to Reverse (R). When the vehicle is restarted, and shifted back into Drive (D), the transmission will then operate in Power Off - Low Default. This default action enables the vehicle to be safely driven to a service center.

Variable Hi and 2-3-4 Clutch Remains Applied

Pressure Control (PC) Solenoid 3 Trim

The PC solenoid 3 trim defaults to its normally high state (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 defaults to its normally closed state (OFF), allowing solenoid 1 signal fluid to exhaust from the shift solenoid valve - mode B.

Shift Solenoid Valve - Mode B

PCS 3 signal fluid pressure acts on a differential area of the shift solenoid valve - mode B, holding the valve in the applied position against shift solenoid valve - mode B spring force. This allows VH 234 clutch/B cooling feed fluid pressure to continue to feed the VH 234 clutch circuit.

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.

Variable Low and 1-2 Reverse Clutch Applies

Pressure Control (PC) Solenoid 3 Trim

The PC solenoid 3 trim defaults to its normally high state (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.

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 block VL 12 reverse clutch feed fluid from entering the VL 12 reverse clutch feedback circuit, and opening the VL 12 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.

Variable Low and 1-2 Reverse Clutch Regulator Valve

PCS 3 signal fluid moves the variable low and 1-2 reverse clutch regulator valve, against variable low and 1-2 reverse clutch regulator valve spring force, to the applied position. This allows line or auxiliary line fluid to pass through the valve into the VL 12 reverse clutch feed circuit.

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.

Shift Accumulation

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.

Variable Hi and 2-3-4 Clutch Accumulator

VH 234 clutch fluid is 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.

Power Off High Default