Chevrolet 2003 Silverado Owner's Manual page 127

Shifting into 2HI
Press and release the 2HI switch. This can be done at
any speed (except when shifting from 4LO).
Shifting into 4LO
To shift to 4LO, the ignition must be in RUN and the
vehicle must be stopped or moving less than 3 mph
(4.8 km/h) with the transmission in NEUTRAL (N). The
preferred method for shifting into 4LO is to have your
vehicle moving 1 to 2 mph (1.6 to 3.2 km/h). Press and
release the 4LO switch. You must wait for the 4LO
indicator light to stop flashing and remain illuminated
before shifting your transmission in gear.
Notice: Shifting the transmission into gear before
the 4LO indicator light has stopped flashing could
damage the transfer case. To help avoid damaging
your vehicle, always wait for the 4LO indicator light
to stop flashing before shifting your transmission
into gear.
It is typical for your vehicle to exhibit significant
engagement noise and bump when shifting between 4LO
and 4HI ranges or from NEUTRAL with the engine
running.
If the 4LO switch is pressed when your vehicle is in gear
and/or moving, the 4LO indicator light will flash for
30 seconds and not complete the shift unless your
vehicle is moving less than 3 mph (4.8 km/h) and the
transmission is in NEUTRAL (N). After 30 seconds the
transfer case will return to the setting last chosen.
Shifting Out of 4LO
To shift from 4LO to 4HI, AUTO 4WD or 2HI your
vehicle must be stopped or moving less than 3 mph
(4.8 km/h) with the transmission in NEUTRAL (N) and
the ignition in RUN. The preferred method for shifting out
of 4LO is to have your vehicle moving 1 to 2 mph
(1.6 to 3.2 km/h). Press and release the 4HI, AUTO
4WD or 2HI switch. You must wait for the 4HI, AUTO
4WD or 2HI indicator light to stop flashing and
remain illuminated before shifting your transmission
into gear.
Notice: Shifting the transmission into gear before
the 4LO indicator light has stopped flashing
could damage the transfer case. To help avoid
damaging your vehicle, always wait for the 4LO
indicator light to stop flashing before shifting your
transmission into gear.
It is typical for your vehicle to exhibit significant
engagement noise and bump when shifting between
4LO and 4HI ranges or from NEUTRAL with the engine
running.
If the 4HI, AUTO 4WD or 2HI switch is pressed when
your vehicle is in gear and/or moving, the 4HI,
AUTO 4WD or 2HI indicator light will flash for
30 seconds but will not complete the shift unless your
vehicle is moving less than 3 mph (4.8 km/h) and
the transmission is in NEUTRAL (N).
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