Pontiac 2006 Montana SV6 Owner's Manual page 386

To release the spare tire from the secondary latch,
do the following:
1. Place the jack under the vehicle, ahead of the rear
bumper. Position the center lift point of the jack
under the center of the compact spare tire.
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2. Turn the folding wrench clockwise to raise the jack
until it lifts the secondary latch device under the
wheel plate.
3. Keep raising the jack until the compact spare tire
stops moving upward and is held firmly in place.
This lets you know that the secondary latch
has released.
4. Lower the jack by turning the folding wrench
counterclockwise. Keep lowering the jack until
the compact spare tire is resting on the folding
wrench.