Chevrolet 2006 Avalanche Owner's Manual page 113

Indicator lights in the button show which setting you are
in. The indicator lights will come on briefly when you
turn on the ignition and one will stay on. If the lights do
not come on, you should take your vehicle to your
dealer for service. An indicator light will flash while
shifting the transfer case. It will remain illuminated when
the shift is complete. If for some reason the transfer
case cannot make a requested shift, it will return to the
last chosen setting.
If the SERVICE 4WD message stays on, you should
take your vehicle to your dealer for service. See "Service
4WD message" under DIC Warnings and Messages
on page 3-53.
Shifting Into Four-Wheel High or AUTO
4WD (Automatic Four-Wheel Drive)
Press and release the Four-Wheel High or AUTO 4WD
button. This can be done at any speed, except when
shifting from Four-Wheel Low, and the indicator light will
flash while shifting. It will remain on when the shift is
completed.
Shifting Into Two-Wheel High
Press and release the Two-Wheel High button. This can
be done at any speed, except when shifting from
Four-Wheel Low.
Shifting Into Four-Wheel Low
To shift to the Four-Wheel Low position, the ignition
must be in RUN and the vehicle must be stopped
or moving less than 3 mph (5 km/h) with the
transmission in NEUTRAL (N). The preferred method for
shifting into four-wheel low is to have your vehicle
moving 1 to 2 mph (1.6 to 3.2 km/h). Press and release
the Four-Wheel Low button. You must wait for the
four-wheel low indicator light to stop flashing and remain
on before shifting your transmission in gear.
Notice: Shifting the transmission into gear before
the Four-Wheel Low indicator light has stopped
flashing could damage the transfer case. To
help avoid damaging your vehicle, always wait for
the Four-Wheel Low indicator light to stop flashing
before shifting the transmission into gear.
It is typical for your vehicle to exhibit significant
engagement noise and bump when shifting between
Four-Wheel Low and Four-Wheel High ranges or from
NEUTRAL with the engine running.
If the Four-Wheel Low button is pressed when your
vehicle is in gear and/or moving, the Four-Wheel Low
indicator light will flash for 30 seconds and not complete
the shift unless your vehicle is moving less than
3 mph (5 km/h) and the transmission is in NEUTRAL (N).
After 30 seconds the transfer case will shift to
Four-Wheel High mode.
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