GMC 2012 Canyon Owner's Manual page 203

For vehicles with a six foot bed,
an upper load platform can be
created by positioning four 5 cm
(2 inches) by 15 cm (6 inches)
wooden planks across the width
of the pickup box. The planks
must be inserted in the pickup
box depressions.
When using this upper load
platform, be sure the load is
securely tied down to prevent it
from shifting. The load's center
of gravity should be positioned
in a zone over the rear axle.
Any load that extends beyond
the vehicle's taillamp area must
be properly marked according to
local laws and regulations.
Remember not to exceed
the Gross Axle Weight
Rating (GAWR) of the rear axle.
When you carry removable
items, you may need to put a
limit on how many people you
carry inside your vehicle. Be
sure to weigh your vehicle
before you buy and install the
new equipment.
Remember not to exceed the
Gross Axle Weight
Rating (GAWR) of the rear axle.
A reinforcement kit for mounting
a toolbox is recommended.
See your dealer.
The vehicle was neither
designed nor intended to carry a
slide-in type camper.