Truck bodies only fit to the chassis models for which they are intended. Although they do only fit a specific number of models, the chassis for these vehicles are commonly used on several makes. There are, however, trucks that utilize a switch-and-go mechanism that allow the body to changed according to the specific need of the driver.
General Motors has several types of platforms commonly used on trucks. Their GMT800 is a shared chassis design that is used among the following vehicles: Chevrolet Silverado, Cadillac Escalade and GMC Sierra.
Switch-and-go systems allow the truck to change out it rear body capabilities. The same truck can become a flatbed, platform truck or storage truck.