Pontiac 2004 Montana Owner's Manual page 426

To release the spare tire from the secondary latch, do
the following:
CAUTION:
{
Someone standing too close during the
procedure could be injured by the jack. If the
spare tire does not slide off the jack
completely, make sure no one is behind you or
on either side of you as you pull the jack out
from the spare.
5-84
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.
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.