I have a 17 year old square tube 16k Reese manual slider. Don't use it much other than backing some times. I keep it maintained so it still slides easily at any angle with 2200-2500 lbs sitting on it. The hitch is still tight with no noise even with a manual NV5600 tranny behind the Cummins.
Many GM owners report they may have a slider but its never used. Some year model GM trucks have a longer dimension from the back of the cab to the trucks rear axle.
My 2500 Dodge has about a 5" shorter dimension and my 5er has a flat profile/square corner so its better to have a slider just in case.