GMC 2014 Sierra Owner's Manual page 443

4. Position the jack under the
vehicle, as shown. 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.
Position the jack under the
vehicle, as shown. If the flat tire
is on the front of the vehicle (all
other models), position the jack
on the frame behind the flat tire.
5. If the flat tire is on the rear, for
1500 models position the jack
under the rear axle about 5 cm
(2 in) inboard of the shock
absorber bracket.