GMC Sierra 2008 Owner's Manual page 129

Shifting In or Out of Four-Wheel-Drive Low
Notice: Shifting the transfer case into
Four-Wheel-Drive Low while moving at speeds
faster than 3 mph (5 km/h) may cause premature
wear to the transfer case, and may cause the
gears to grind. To avoid causing premature wear,
and grinding the gears, do not shift the transfer
case into Four-Wheel-Drive Low while the vehicle
is moving faster than 3 mph (5 km/h).
Shifting into Four-Wheel-Drive Low should be done,
if possible, with the vehicle at a slight roll, 3 mph
(5 km/h) or less.
•
Shift the transmission into NEUTRAL (N).
CAUTION:
{
Shifting the transfer case to NEUTRAL
can cause your vehicle to roll even if the
transmission is in PARK (P). 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.
•
Shifting into Four-Wheel-Drive Low with the vehicle
at a stop may be more difficult. You may be unable
to complete the shift to Four-Wheel-Drive Low, and
will end up in NEUTRAL. This is normal, and is a
function of the gear teeth aligning in your transfer
case. When this happens, make sure the engine is
on, shift your transmission momentarily to drive and
back to NEUTRAL, and then complete the shift.
•
Shift the transfer case shift lever in one continuous
motion into the Four-Wheel-Drive Low position.
•
When Four-Wheel-Drive Low do not drive faster than
45 mph. This will reduce wear and extend the life of
your transfer case.
Shifting In or Out of NEUTRAL
1. With the vehicle running and the engine at an idle
set the parking brake.
2. Place the transmission into NEUTRAL (N).
Shift the transfer case in one continuous motion into
or out of the NEUTRAL position.
2-39