I just picked up a 2015 Silverado 2500HD, it never had a tow hitch installed on it and I would like to install one myself. I don't have a trailer at this time and will be using the truck for hauling m...
The factory receiver on the GM trucks is 2.5" square, which I guess could be called "Class 5" even though there is no such thing.
In the past factory receivers were rated for 750/7500 without WD and 1250/12500 with a WD hitch. That was the rating on my 3500's OEM anyway.
So, you want something rated for AT LEAST that much if not more. IMHO you should shoot for something with a 1500/15000 tongue/trailer rating (with WD).