GMC 2015 Sierra Owner's Manual page 304

helps when driving on snowy or icy
roads, when off-roading, or when
plowing snow.
The vehicle can be shifted between
2 and 4 while the vehicle is
moving. In extremely cold weather,
it may be necessary to stop or slow
the vehicle to shift into 4 .
Using the Manual Transfer Case
Use quick motions to shift into or
out of 4 or N (Neutral).
Shifting may be harder when the
vehicle is cold, but will return to
normal once warmed up.
Four-wheel drive reduces fuel
economy.
Shifting from 2 to 4
Shifts can be made at any
vehicle speed.
Shift in one continuous motion.
Shifting while the vehicle is in
motion may require that
moderate force be applied to the
shift lever before 4 can be
engaged, especially in cold
weather.
In extremely cold weather, it may
be necessary to slow or stop the
vehicle to shift.
While in 4 , the vehicle can be
driven at any posted legal speed
limit.
Shifting In or Out of 4
Caution
Shifting the transfer case into 4
while moving at speeds faster
than 5 km/h (3 mph) may cause
premature wear to the transfer
case, and may cause the gears to
grind.
1. If possible, shift with the vehicle
moving 5 km/h (3 mph) or less.
2. Shift the transmission into
N (Neutral).
Driving and Operating
3. Shift the transfer case shift lever
in one continuous motion.
4. Shifting with the vehicle at a stop
may be more difficult. It is
possible that the shift will not
complete and the transfer case
will remain in N (Neutral). This is
normal. To complete the shift,
with the engine running, shift the
transmission to D (Drive) and
back to N (Neutral), and
reattempt the transfer case shift.
Shifting In or Out of Neutral
1. Have the engine running.
2. Set the parking brake. Press and
hold the brake pedal. See
Parking Brake on page 9-48.
3. Place the transmission into
N (Neutral).
4. Shift the transfer case lever in
one continuous motion into or
out of N (Neutral).
9-41