Diesel Data: Automotive Repair

Neutral




Neutral

When the gear selector lever is moved to the Neutral (N) position, the hydraulic and electrical system operation is identical to Park (P) range. However, if Neutral is selected after the vehicle was operating in Reverse (R), the following changes would occur in the hydraulic system.

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 Low and 1-2 Reverse Clutch Releases

If the transmission is operating in Reverse - Series Mode when a shift to Neutral occurs, the variable low and 1-2 reverse clutch is released.

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 clutch regulator valve; the variable low and 1-2 reverse 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 clutch feed fluid circuit and is routed to the variable low and 1-2 reverse clutch regulator valve.

Variable Low and 1-2 Reverse Clutch Boost Valve

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

Variable Low and 1-2 Reverse Clutch Regulator Valve

Variable low and 1-2 reverse clutch regulator valve spring force moves the variable low and 1-2 reverse clutch regulator valve to the released position, allowing VL 12 reverse 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.

Variable Hi and 2-3-4 Clutch Releases

If the transmission is operating in Reverse - Output Split when a shift to Neutral occurs, the variable hi and 2-3-4 clutch is released.

Shift Solenoid 2

The shift solenoid 2 defaults to its normally closed state (OFF), allowing solenoid 2 signal fluid to exhaust from the shift solenoid valve - mode A, the variable hi and 2-3-4 clutch regulator valve, and the 1-3 reverse clutch regulator 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

Shift solenoid valve - mode A spring force moves the shift solenoid valve - mode A to the released position, allowing 234 clutch feed fluid pressure to exhaust through the valve.

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 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.

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.

Neutral