2008 GMC Sierra 1500 Pickup Owner's Manual - Page 396

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 5-91. 5. Use the wheel wrench which has a hook that lets you pull the hoist cable toward you to assist in reaching the spare tire. 6. Tilt the tire toward the vehicle with some slack in the cable to allow access to the tire/wheel retainer (D). Separate the retainer from the guide pin by sliding the retainer up the pin while pressing down on the latch. 5-84