Pontiac 2005 Aztek Owner's Manual page 111

If you have the luggage carrier, you can load things on
top of your vehicle. If you do load things on the top
of your vehicle, you must load them on the luggage
carrier crossrails. These are available from your dealer.
The luggage carrier has four tie-down loops on the
inside of each right and left side rail. These let
you secure cargo placed on the crossrails, as long as
they are not wider or longer than the luggage carrier.
Notice: Damage may be caused to the roof of your
vehicle if anything is placed directly on the roof.
Notice: Loading cargo on the luggage carrier that
weighs more than 220 lbs (100 kg) or hangs over
the rear or sides of the vehicle may damage
your vehicle. Load cargo so that it rests on the slats
as far forward as possible and against the side
rails, making sure to fasten it securely.
When you carry cargo on the luggage carrier of a
proper size and weight, put it on the slats and distribute
the weight evenly. Then slide the crossrail up against
the rear of the load to keep it from moving. You can then
tie it down. Cargo containers must be loaded on the
crossrails only.
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