GMC 2009 Yukon XL Owner's Manual page 500

5. Raise the tire part way upward. Make sure the
retainer is seated in the wheel opening.
6. Raise the tire fully against the underside of the
vehicle by turning the wheel wrench clockwise
until you hear two clicks or feel it skip twice.
You cannot overtighten the cable.
5-104
4. Insert the open end of
the extension (J)
through the hole in the
rear bumper (I) (hoist
shaft access hole).
7. Make sure the tire is stored securely. Push, pull (A),
and then try to turn (B) the tire. If the tire moves,
use the wheel wrench to tighten the cable.
8. Reinstall the spare tire lock.
9. Reinstall the hoist shaft access cover.