Think of it like this, cargo capacity is how much weight your suspension and frame can support. Towing capacity is how much weight your engine can pull. Even though all your camper weight is on the truck, your engine still needs to pull it around. If you had a 5000lb trailer, the trailer's weight would be partially carried by the truck and the rest on the trailer wheels. Your engine would still need to pull 5000lbs behind it even though 500lbs would be on the truck.
2021 Transcend Xplor 247BH
Husky WDH with Sway Control
2013 Chevy Silverado 2500HD LTZ 6.6L V8 Duramax
Forever in my memory. Forever in my heart.
Laurie J. Wood 3/22/67 - 8/23/19