GMC Yukon Denali 2006 Manual page 392

2. Assemble the wheel wrench (H) and the two jack
handle extensions (I) as shown.
5-80
Be sure the hoist end of the extension connects to
the hoist shaft (E). The ribbed square end of the
extension is used to lower the spare tire.
4. Turn the wheel wrench (H) counterclockwise to
lower the spare tire to the ground. Continue to
turn the wheel wrench until the spare tire can be
pulled out from under the vehicle.
If the spare tire does not lower to the ground, the
secondary latch is engaged causing the tire
not to lower. See Secondary Latch System on
page 5-88.
3. Insert the spare tire
end (open end) (F)
of the extension
through the hole (G)
in the rear bumper.