GMC Yukon XL Denali 2005 Owner's Manual page 386

2. Assemble the wheel wrench (H) and the two jack
handle extensions (I) as shown.
5-78
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 5-86.
3. Insert the hoist end
(open end) (F) of the
extension through
the hole (G) in the rear
bumper.