Shifting Into Four-Wheel Drive High or AUTO (Automatic Four-Wheel Drive)

GMC Sierra / GMC Sierra Owners Manuals / Driving and Operating / Drive Systems / Four-Wheel Drive / Shifting Into Four-Wheel Drive High or AUTO (Automatic Four-Wheel Drive)

Turn the knob to the Four-Wheel Drive High or AUTO position. This can be done at any speed, except when shifting from Four-Wheel Drive Low. The indicator light will flash while shifting. It will remain on when the shift is completed.

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    General Information
    For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people. Genuine GM parts have one of these marks: ...

    Manual Operation
    (Fan Control): Press these buttons to increase or decrease the fan speed. Pressing either fan button while in automatic control places the fan under manual control. The fan setting remains displayed ...

    Footnotes — Maintenance Schedule Additional Required Services — Normal
    a) Or every two years, whichever comes first. More frequent replacement may be needed if the vehicle is driven in areas with heavy traffic, areas with poor air quality, or areas with high dust levels. ...