2021 Short bed vs long bed
2500 Crew Turning diameter, curb-to-curb, ft. (m) 52.7 (16.1) 57.0 (17.4)
3500's are the same
4wd crew longbox payloads
2500 Payload, L5P, lbs. (kg) 17” wheels, lbs. (kg) 3426 (1554)
2500 Payload, L5P, lbs. (kg) 18” or 20” wheels, lbs. (kg) 3597 (1632)
3500 srw Payload (with Single Rear Wheels), L5P, lbs. (kg) 4078 (1850)
3500 drw Payload (with Dual Rear Wheels), L5P, lbs. (kg) 5607 (2543)
All drws are long box.
On previous generations all dmaxes and 3500 gas got the larger rear differential.
New axles for 2020+. I don't recall if this is still true.