Chevrolet 2002 Silverado 1500 Pickup Owner's Manual page 282

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" in the Index.
4-54
2-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. The zone is located in the area
between the front of each wheel well and the rear of
each wheel well. The center of gravity height must not
extend above the top of the pickup box flareboard.
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 front or rear axle. See "Loading Your
Vehicle" in the Index.