GMC Hummer H3 2008 Owner's Handbook Manual page 197

Starting and Operating Instructions
D (Drive)
This position provides the best fuel
economy for your vehicle.
Use this position for normal driv-
ing in most street and highway
situations. If you need more power
and are:
• going less than about 55 km/h
(35 mph), push your accelera-
tor pedal about halfway down.
• going more than about
55 km/h (35 mph), push the
accelerator all the way down.
. . . 196
When slippery road conditions
exist, down-shifting the transmis-
sion may cause skidding.
When towing a trailer with an
automatic transmission, operate
your vehicle in D (Drive).
You may want to shift into 3
(Third) or, if necessary, a lower
gear if the transmission shifts too
often.
3 (Third Gear)
This position is also used for
normal driving.
This position reduces vehicle
speed even more than D (Drive)
without using the brakes.
Use this gear when climbing hills
and for engine braking when driv-
ing down steep hills.