GMC 2013 Sierra Owner's Manual page 447

For all other models, position the
jack under the rear axle between
the spring anchor and the shock
absorber bracket.
If a snow plow has been added
to the front of the vehicle, lower
the snow plow fully before
raising the vehicle.
Make sure that the jack head is
positioned so that the rear axle
is resting securely between the
grooves that are on the
jack head.
Getting under a vehicle when it is
lifted on a jack is dangerous.
If the vehicle slips off the jack,
you could be badly injured or
killed. Never get under a vehicle
when it is supported only by
a jack.
Raising the vehicle with the jack
improperly positioned can
damage the vehicle and even
make the vehicle fall. To help
avoid personal injury and vehicle
damage, be sure to fit the jack lift
head into the proper location
before raising the vehicle.
6. Turn the wheel wrench
clockwise to raise the vehicle.
Raise the vehicle far enough off
the ground so there is enough
room for the spare tire to fit
under the wheel well.
7. Remove all the wheel nuts and
take off the flat tire.
Rust or dirt on a wheel, or on the
parts to which it is fastened, can
make wheel nuts become loose
after time. The wheel could come
off and cause an accident. When
(Continued)