GMC 2010 Sierra - Manual (Page 179)

A parking brake symbol
is located next to the
N (Neutral) symbol as a
reminder to set the
parking brake before
shifting the transfer case
into N (Neutral).
{ WARNING:
Shifting the transfer case to Neutral can cause the
vehicle to roll even if the transmission is in
P (Park). You or someone else could be seriously
injured. Be sure to set the parking brake before
placing the transfer case in Neutral. See Parking
Brake on page 3‑54.
N (Neutral): Shift to this setting only when the vehicle
needs to be towed. See Recreational Vehicle Towing on
page 5‑49 or Towing Your Vehicle on page 5‑48.
2
m
(Two-Wheel-Drive High): This setting is used for
driving in most street and highway situations. The front
axle is not engaged in two-wheel drive. This setting also
provides the best fuel economy.
4
m
(Four-Wheel-Drive High): Use this setting when
you need extra traction, such as on snowy or icy roads
or in most off-road situations. This setting also engages
the front axle to help drive your vehicle. This is the best
setting to use when plowing snow.
You can shift from Two-Wheel-Drive High to
Four-Wheel-Drive High or Four-Wheel-Drive High to
Two-Wheel-Drive High while the vehicle is moving.
In extremely cold weather, it may be necessary to stop
or slow the vehicle to shift into Four-Wheel-Drive High.
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