GMC 2004 Sierra - Manual (Page 131)

Recommended Transfer Case Settings
Transfer Case Settings
Driving Conditions 2HI 4HI 4LO N
Normal YES
Severe YES
Extreme YES
Vehicle in Tow* YES
*See Recreational Vehicle Towing on page 4-54 or
Towing Your Vehicle on page 4-53 for further
information.
An indicator on the bezel near the lever shows you the
transfer case settings:
2-Wheel High (2HI): This setting is used for driving in
most street and highway situations. Your front axle
is not engaged in two-wheel drive. This setting
also provides the best fuel economy.
4-Wheel High (4HI): Use 4HI when you need extra
traction, such as on snowy or icy roads or in most
off-road situations. This setting also engages your front
axle to help drive your vehicle. This is the best setting
to use when plowing snow.
{ CAUTION:
Shifting the transfer case to NEUTRAL can
cause your vehicle to roll even if the
transmission is in PARK (P), or if you have a
manual transmission, even if you are in gear.
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 2-48.
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