Had a 2015 Max tow GMC 1500 If memory serves me wright it had 4300 lb. rear axle and around 1800 payload . I think the standard rear axle is 3850 lbs. I had a 28 foot Keystone bullet that was right around 6500 lbs. Truck handled it fine but you could never drive with one hand . Trailer didn’t sway but truck was constantly moving around probably because it had 20 inch P rated tires . I don’t get it you buy max tow / max payload and they give you P rated tires shame on GM . Kept it two years and got a 2017 GMC 2500 HD problem solved