GMC 2008 Envoy - Manual (Page 380)

4. Turn the wheel wrench counterclockwise to lower
the spare tire. Keep turning 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 5-92
for more information.
5. Tilt the retainer at the end of the cable when the
tire has been completely lowered, and pull it
through the wheel opening.
6. Pull the tire out from under the vehicle.
Notice: If you drive away before the spare tire or
secondary latch system cable has been reinstalled,
you could damage your vehicle. Always reinstall
this cable before driving your vehicle.
7. Put the spare tire near the flat tire.
5-86