GMC 2003 Sierra - Manual (Page 130)

To shitt from 2HI or dHI TO 4L0i the vehicle must be
slopped or moving less than 3 mph (4.e km/h) iwiih the
transmission in NEUTRAL fN). The preterred melhod
far shifting into 41.0 is to have your \/ehicie moving i to
2 mph {1.6 to
3.2 km/h). Press and raJease the 4LO
switch. You musl wail for Ihe 4LO indicator light lo slop
flashing and remain illuminated cefore shilling your
transmission into gear
If the 4L0 switch is prassed when your vehicle is In
gear
and/or moving, the 4L0 irdicalor light will flash for
30 seconds and not complele I he shift unlass your
vehicle is moving slower than 3 mph [4.6 km/h) and the
transmission is in MEUTRAL [T^K Tlie transfer case
will shift to 4HI while waiting to
oomplelE the shift.
Shifting from 4LO to 4HI or 2Hl
To shift from 4LO lo 4HI or 2HI. your vehicle must be
stopped or moving less than
2 mph (4.3 km/h) with,
the transmiBSion in NEUTRAL (N). The preterred melhod
for shifting out of 4LO is to have your vehicle moving
1 to 2 mph [1.S to 3.2 km.'h). Press and release Ihe 4Hl
swilch. You must wait lor the 4HI indicator light to
slop flashing and remain illuminaled before shifting your
transmission info gear.
Shifting from ZHI or 4HI to 4LO
tr Ihe 4Hl switch ia pressed whan yout vehicle i& in gear
and/'or moving, itie 4Hl indicator lighi wHi flash for
30 seconds hut will not complete Ihe shill unless the
vehicle
is moving slower lhan 3 mph (4.3 km/h) and the
iransmissioni is in NEUTRAL (N).
Shifting into NEUTRAL
In shift Ihe transfer case to NEUTRAL, first make sure
the vehicle is parked so ihal il will not roil:
1. Set Ihe parking brake.
2. Slart the vehicle or turn the ignition to RUN,
3. Connect Ihe vehicle to the towing vehicle.
4. Pul the transmission In NEUTRAL (N).
6. Shift the transfer ease (o 2HI.
5. Simultaneously press and hold the 2HI and 4LO
bultons for 10 seconds. The red NEUTRAL light
will come on when the transfer case shilt lo
NEUTRAL is complete,
7. Shitt Ihe transfJiissioin. to REVERSE (R) for one
second, Then shift ihe transmission to DRIVE (D)
for ona second
B. Turn !he ignition lo OFF,
9, Place the transmission shift lover in PARK (P).
10. Release the parking brake prior to towing
2^3