GVW is Gross Vehicle Weight. That is the most the truck is allowed to weigh fully loaded. To find out how much the truck can carry, weigh it empty and subtract that weight from the GVW. For example, I had a 1-ton that had a GVW rating of 9.000 lb. It weighed 6.000 lb. empty, so it could haul 3,000 lb. safely. My wife once had a 1/2-ton that could only carry 666 lb. hat truck can carry I have a 2-ton with a 15,000 lb. GVW rating that weighs around 6,500 lb. empty. That truck can carry over 4 tons, but is called a 2-ton. The nomenclature of 1/2-ton, 1-ton, 2-ton, etc. just names the series of truck, not the payload rating.
The same applies to axle ratings. The rating is the most the axle can weigh. The axle ratings usually add up to more than the GVW to allow for loads that are not perfectly balanced. You can easily overload an axle without overloading the truck if you aren't paying attention.
