The terms; 1/2 ton, 3/4 ton, and 1 ton are archaic now. The new normal is series 1, series 2, and series 3. Don't forget series 4 and 5. That covers all brands. Now, this is where it gets weird. For a lot of reasons, you can now buy almost all these trucks in many weight ratings, mostly to do with platform: i.e.: 4WD/2WD/Diesel/Gas/ stripped or loaded. The boundaries of say, 1 series trucks, especially with Ford has stretched out mostly to the higher weight rating side with a much wider splay of offerings. Some 1 series trucks can actually out carry some 2 series trucks with the right choices.
jefe