[GTyankee]

One other bit of information,

FCA/Chrysler Engineers always under rated the Tow/Haul capacities of the trucks
At the same time Ford always over rated theirs to get better sales

Because of this, the US Government got involved & came up with a voluntary Standard

Ford fought like hell to stall the new Standard J2807, Ford finally complied when they went with the Aluminum Body

The first Rams built to meet the new voluntary standard was in 2014
Ram certified its 2014 and 2015 Ram 2500 and 3500 products to J2807

The standard sets minimum performance levels, but automakers can always decide to trade away the highest possible rating in favor of more performance or ride comfort. Nothing in J2807 says you can't under-rate your SUV or truck on purpose.
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New calculations for trailer weight ratings: In addition to the performance standards, SAE J2807 also uses a specific set of assumptions to calculate maximum trailer weight ratings:

For light-duty full-size pickups (GVWR < 8,500 lbs.), SAE J2807 assumes that the tow vehicle includes any options with higher than 33 percent penetration;
It assumes there is both a driver and passenger in the vehicle, each weighing 150 pounds;
It assumes that tow vehicles also include up to 70 pounds of aftermarket hitch equipment (where applicable); and
For conventional trailer towing, SAE J2807 assumes that 10 percent of the trailer weight is on the tongue.