Found this article and it explains the GVWR: http://vehicleweight.net/
Might be helpful for others - you are probably right about the weight of my truck - I'm thinking around 4600# - Thanks for your help!
What Is Gross Vehicle Weight Rating And How Does It Work?
The gross vehicle weight rating is a weight limit that is imposed on your vehicle. This limit is set by the manufacturer of the vehicle. When calculating the gross vehicle weight rating often called (GVWR), a number of factors are taken into consideration. These include the base curb weight of your vehicle, the weight of any optional items, your cargo, and your passengers.
The main reason for gross vehicle weight rating is for safety. If you overload any vehicle, a number of safety issues can arise. If your vehicle is too heavy, the brakes may not be strong enough to stop or slow down quickly enough. Your suspension can also be damaged if you have too much weight in your vehicle. There are a number of other potential hazards that can occur, and that is why is it important to both know and adhere to your vehicle’s weight rating.
The gross vehicle weight rating is not how much your vehicle weighs, but how much weight your vehicle can have at any given time. This is the maximum amount, and it includes your passengers, your fuel, and any additional items you may be carrying.
What’s The Difference Between Curb Weight, Gross Vehicle Weight, And Gross Vehicle Weight Ratings?
These are three common terms that can easily be confused. The vehicle curb weight is the actual weight of your vehicle without any passengers or cargo. It is referred to as the base weight, and this weight is used when calculating the gross vehicle weight or the weight of a fully loaded vehicle. The gross vehicle ratings are different, as well, and these are the ratings that decide the amount of weight that a vehicle can have when it is filled with fuel and loaded to its maximum capacity.