GMC 1995 Safari Owner's Manual page 168

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 transmission overheating.
When towing at high altitude on steep uphill grades, consider the following:
Engine coolant will boil at a lower temperature than at normal altitudes. If
you turn your engine off immediately after towing at high altitude on steep
uphill grades, your vehicle may show signs similar to engine overheating.
To avoid this, let the engine run while parked (preferably on level ground)
with the automatic transmission in PARK
(P) for
a few minutes before
turning the engine off. If you do get the overheat warning, see "Engine
Overheating" in the Index.
Parking on Hills
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. Turn your
wheels into the curb when facing downhill and away from the curb
when facing uphill.
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 to
5. Release the regular brakes.
PARK (P).
When You Are Ready to Leave After Parking on a Hill
1. Apply your regular brakes and hold the pedal down while you:
0
Start your engine;
0
Shift into a gear; and
0
Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
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