Chevrolet Impala 2007 Impala Owner's Manual page 293

Driving On Grades
Reduce speed and shift to a lower gear before
you start down a long or steep downgrade. If you
don't shift down, you might have to use your
brakes so much that they would get hot and no
longer work well.
On a long uphill grade, shift down and reduce
your speed to around 45 mph (70 km/h) to reduce
the possibility of engine and transaxle overheating.
Notice: When the outside temperature is
above 100° F (38° C) and/or there is a steep,
continuous grade, the recommended speed
when towing is 55 mph (88 km/h) or less.
Extended higher than normal engine and
transaxle temperatures may damage your
vehicle.
If you have overdrive, you may want to drive in
THIRD (3) instead of DRIVE (D).
Parking on Hills
CAUTION:
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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,
here's how to do it:
1. Apply your regular brakes, but don't shift into
PARK (P) yet.
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 then shift to PARK (P).
5. Release the regular brakes.
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