Your truck has 2 ratings. GROSS VEHICLE WEIGHT RATING and GROSS COMBINED WEIGHT RATING.
GVWR is for the truck. GCWR is for the truck and trailer.
GVWR for a Hemi 4x4 1500 is 7100 (7200 now for 2020 diesel) has nothing to do with anything but it being a 4x4 (2wd is 6900)
Gross Axle Weight Ratings are 3900 front and 4100 rear. each for 4x4. Which, yes goes to 8000...but there are other things getting us back to 7100.
GCWR is based solely on rear gear ratio.
3.21 is 13900 and 3.92 is 17000. Read the charts explanation and you will u understand why.
So now...
Final # is on the door sticker. Don’t forget that fuel & passengers count as payload.
Fuel IS NOT payload, it is part of base weight. With a full tank you still have all that payload listed.(as you drive and use fuel or start with less than a full tank...you actually gain payload) Payload is GVWR minus base weight. Base weight is the truck with all factory options and all fluids. But, yes passengers are payload so are not accounted for in the payload rating and would take away from it.
Passengers are included in GCWR...to the tune of 300 lbs. So, figure accordingly. The chart says 2 passengers at 150lbs...I weigh 295.
Also included is hitch weight of 70 and 10% tongue weight.
Easy to see how the max towing is that...MAX...never to be achieved unless you only have 300lbs of cargo and a very light tongue weight on trailer.
So, at the end of the day the max a RAM 1500 can weigh on a CAT scale with a trailer is 17000lbs. Each axle has to be under 3900, with the truck not exceeding 7100.
It is that simple. Be careful if you decide to exceed any one of the numbers.
And yes, options and mods do affect both payload and GCWR.