The 3/4-ton Duramax and the 2500HD models are likely equipped and rated to pull a heavy load. My own 2500 is rated to pull 9,500 while the 3500 it replaced was rated for 10,000. My co-workers 2500HD is rated for even more using a class 5 hitch. I don't recall the exact figure but it is something like 13,000 or 14,000.
The capacity of the truck is only part of the equation. Knowing the hitch capacity is another, my 10,000 pound rated truck had a 6,000 rated hitch when I bought it. The 9,500 pound rated truck came with a 10,000 rated hitch.
If the truck is equipped to deal with the load, the 'class' of the truck doesn't really matter. I'm skeptical any 1/2-ton, even a heavy half like the F150 would really be a good safe option for pulling a 5,000 pound truck on a 1,700 to 2,000 pound trailer. It certainly would have no margin for error. And I don't even want to think about using an S-10...
