Pontiac 2006 Montana SV6, Owner'S Manual, Page: 302 / 454

Driving on Grades
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade. If you do not shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
If you are towing a trailer that weighs more than
1,000 lbs (450 kg), you may prefer to drive in THIRD (3)
instead of AUTOMATIC OVERDRIVE (D) or, as you
need to, a lower gear. This will minimize heat build-up
and extend the life of your transaxle.
Parking on Hills
{
CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, do the
following:
1. Apply your regular brakes, but do not shift into
PARK (P).
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake, and shift into PARK (P).
5. Release the regular brakes.
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