GMC 2006 Sierra 1500 Pickup Owner's Manual page 518

4. Repeat this procedure at least two times. If the
spare tire lowers to the ground, continue with
Step 5 of Removing the Spare Tire and Tools on
page 5-92.
5. Turn the wrench counterclockwise until
approximately 6 inches (15 cm) of cable is exposed.
6. Stand the wheel blocks on their shortest ends,
with the backs facing each other.
5-106
7. Place the bottom edge
of the jack (A) on the
wheel blocks (B),
separating them so that
the jack is balanced
securely.
8. Attach the jack handle, extension, and wheel wrench
to the jack and place it (with the wheel blocks) under
the vehicle towards the front of the rear bumper.