2003 GMC Sonoma Owner's Manual - Page 252

Payload The payload capacity is shown on the Certification/Tire label. This is the maximum load capacity that your vehicle can carry. Be sure to include the weight of the occupants as part of your load. If you added any accessories or equipment after your vehicle left the factory, remember to subtract the weight of these things from the payload. Your dealer can help you with this. Remember not to exceed the Gross Axle Weight Rating (GAWR) of the front or rear axle. See Loading Your Vehicle on page 4-49. 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. See Loading Your Vehicle on page 4-49. 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. 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. Notice: Your warranty does not cover parts or components that fail because of overloading. Remember not to exceed the Gross Axle Weight Rating (GAWR) of the rear axle. See Loading Your Vehicle on page 4-49. 4-51