2004 GMC Canyon Owner's Manual - Page 250

Two-Tiered Loading By positioning four 2" X 6" wooden planks across the width of the pickup box, you can create an upper load platform. The planks must be inserted in the pickup box depressions. The length of the planks must allow for at least a 3/4 inch (2 cm) bearing surface on each end of the plank. 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. Add-On Equipment 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. Notice: Overloading your vehicle may cause damage. Repairs would not be covered by your warranty. Do not overload your vehicle. Remember not to exceed the Gross Axle Weight Rating (GAWR) of the rear axle. 4-58