Hummer 2007 H3 Owner's Manual page 398

Rear Positions
Refer to the graphic above to locate the
placement of the jack if the flat tire is on the
rear of the vehicle.
398
Rear Tire Flat: You will need to use the jack
handle and both jack handle extensions.
Attach the wheel wrench to the jack
extensions. Attach the jack handle to the jack.
From the rear of the vehicle align the jack
under the rear axle. Turn the wheel wrench
clockwise to raise the vehicle. Raise the
vehicle far enough off the ground so there is
enough room for the spare tire to clear
the ground.