Pontiac 2007 G6 Owner's Manual page 303

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
is how to do it:
1. Apply your regular brakes, but do not shift into
PARK (P) for an automatic transaxle or into
gear for a manual transaxle. When parking
uphill, turn your wheels away from the
curb. When parking downhill, turn your wheels
into the curb.
2. Have someone place chocks under the trailer
wheels.
3. When the 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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