GMC 2015 Sierra Owner's Manual page 446

3. Use the wheel wrench and turn it
counterclockwise to loosen the
wheel nuts. Do not remove the
wheel nuts yet.
Front Position 1500 Models
4. If the flat tire is on the front of
the vehicle (1500 models),
position the jack under the
bracket attached to the vehicle's
frame, behind the flat tire, as
shown.
Vehicle Care
Front Position All Other Models
If the flat tire is on the front of
the vehicle (all other models),
position the jack under the
vehicle, as shown.
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