I had a yard and a half of 5/8 crushed rock tip scales at rock quarry at almost 12k
figured about 4200lbs I'd have to say the front end was a little light but other than that no problems 01 2500

 

I had about 3500# of scrap iron in mine. Put some dents in the floor of the bed from loading the 750# weights off of an oil well pumping unit oops. anyway I could tell it was back there but the truck would still slip the tires on slightly damp pavement, couldn't skid your feet so pretty dry. Sure floated acros the woops and bumps of the road but never got close to the bumpstops.

 

Heaviest load I ever had was a 600 lb wood-burning stove in the bed with the 200 lb tool box (full), me driving (150 lbs... yes I'm a scrawny guy) and about 350 lbs of passengers.

Now towing is another matter entirely.

 

700 lbs of smow plow in the front squats the front 1-2"

750 lbs of salt between the axle and tailgate me and a friend standing on the tailgate (at least 450 lbs) loading - 1200 lbs total + plow. Rear didn't squat at all.

Couldn't even tell I was loaded while driving.