DYNAMIC TORQUE CONTROL 4WD/AWD SYSTEM


  1. OUTLINE


    1. A GF1A type transfer that is compact and lightweight is used on 4WD/AWD models.

    2. A dynamic torque control 4WD/AWD is used on 4WD/AWD models.

    3. The dynamic torque control 4WD/AWD is a compact, lightweight and high performance 4WD/AWD system that optimally controls the torque distribution to the front and rear wheels using an electromagnetic control coupling in the rear differential.

    4. The 4WD/AWD system performs control in cooperation with the brake control system. The 4WD ECU assembly controls the drive torque distribution to the front and rear wheels in accordance with information received from the skid control ECU. These controls ensure a smooth acceleration and driving stability. For details, see the Brake Control/Dynamic Control Systems section.

  2. SPECIFICATION

    Transfer Type GF1A
    Gear Type Hypoid Gear
    Gear Ratio 0.439
    Transfer Ring Gear The No. of Teeth 41
    Transfer Driven Pinion Gear The No. of Teeth 18
    Oil Viscosity SAE 75W-85
    Oil Grade API GL-5
    Oil Capacity 0.45 Liters (0.48 US qts, 0.41 Imp. qts)
    Weight (Reference)* 11 kg (24.9 lb)

    Tech Tips

    *: The weight shown is the weight of the part fully filled without fluid.

  3. MAIN FEATURES


    1. Based on information provided by various sensors, the 4WD ECU assembly controls the amperage applied to the electromagnetic control coupling in order to transmit an appropriate amount of drive torque to the rear wheels when needed. The following describes the features and benefits of the dynamic torque control 4WD/AWD:

      Feature Outline
      Traction Performance Achieves stable start-off and acceleration performance.
      Driving Stability Performance Achieves stable cornering performance.
      Fuel Economy Achieves better fuel economy by transmitting drive torque to the rear wheels when needed, in the amount needed.

    2. A differential lock switch has been provided. This enables the driver to select between the Auto and Lock modes by operating the switch. The system optimally controls the torque distribution to the front and rear wheels in the respective modes.

      Mode Differential Lock Switch Differential Lock Indicator Light Outline
      Auto Off Off

      • Optimally distributes drive torque to the front and rear wheels.

      • Ensures optimal start-off performance during a start-off based on information provided by various sensors.

      • Suppresses the tight corner braking phenomenon* during low-speed cornering.

      • Reduces the amount of torque distribution to the rear wheels and improves fuel economy when the system judges that the vehicle is traveling steadily.

      • Disengages the 4WD/AWD during braking deceleration.
      Lock On On

      • Distributes the maximum torque limit to the rear wheels.

      • Distributes the maximum torque limit to the rear wheels during start-off.

      • Distributes optimal torque during low-speed cornering.

      • Disengages the 4WD/AWD during braking deceleration.

      • Disengages Lock mode and transfers to Auto mode when the vehicle speed exceeds 40 km/h (25 mph).

      Tech Tips

      *: Tight corner braking phenomenon: a phenomenon in which a 4WD/AWD vehicle may lurch and decelerate due to a rotational speed difference between the front and rear wheels, such as during low-speed cornering in 4WD/AWD mode.

    3. A Sport mode switch has been provided on models with VSC excluding 2WD models with manual transaxle. This enables the driver to select Sport mode by operating the switch. The 4WD ECU assembly performs cooperative control with the skid control ECU, ECM and power steering ECU assembly in addition to 4WD/AWD control when in Auto mode, thus regulating torque distribution to the front and rear wheels in order to ensure operability and stability during sporty driving.