i had 50 60lb bags of concrete in my 2500hd and that was the limit, it was swaying a little over bumps
I really wouldn't say that is overloaded too bad. Driving with common sense, being prepared for stops, and others safety is the main thing. People tend to think trucks will not take as much as they can. I have a bit of experience here and will give you some examples.
I worked at an AG, liquid fertilizer business for over 10 years. We had a '76 3/4 and '78 1 ton Chevy with 500 gallon tanks on the back, 5 HP gas motor/circulator pump 40 ft booms and cast iron ground driven John Blue pumps. Spray rig weighed over 2000 lbs. 500 gallon of water weighs 4150 lbs. If we were spraying 32% nitrogen, 500 gallon weighed 5500 lbs. Trucks went out constantly with 500 gallon and I'd run 3 full tanks of fuel a day.
Things broke occasionally but the conditions were about as rough as they come. We'd spray over mulboard plowed ground with all that weight some times, Frame broke in two on the 3/4 ton just ahead of the front rear axle spring perch. Tore it down, welded it back up with a fishplate and never broke again. We put in an extra leaf when we first got them and did have them break occasionally. I think one time the top gave out on me but I was bouncing pretty hard. Transmission were the weak link as pulling that much weight through soft , fluffy ground in low lock made some pretty serious heat with an automatic. Shifting gears was out as you need your hand to drive and run the controls.
Never had an axle issue with the Dana 60 fronts or 14 bolt rears. I bought the 1 ton from them before I left and it's the frame under the truck in my avatar. The 14 bolt was wore out and I replaced it but it was still working. Just wore shafts and a slight bow in the tube. They replaced them with Cummins Dodges and it was the same thing, 727 trans. gave out in one year.
These were all single wheel rear trucks, Had to have that to get between the rows.
One other thing I'll mention was the tires. While I was running the Chevys only had a blowout once and that was my fault. Cord showing on the inner rear and it went. When we got the Dodges we got Michelins from the factory. They had belt shifts left and right and started blowing within 6 months of use. They bought 3 trucks and out of 14 tires 6 blew with a year and I told the bosses wife that I refused to drive them anymore till we changed them out. We went with non E rated tires and never had another issue. I've since had belt shifts on my personal Dodge which hasn't been overloaded. It too had E rated tires so I'm not a real fan of them. Might be just the new compounds or the stiffness of the steel plys. What gets me is we ran every generic tire you could imagine that wasn't load rated for what we were subjecting them to and they took it till they were bald. Now a tire that's supposed to be tougher can't?
My old 1/2 ton pictured previously has never had a tire issue either with standard tires and I HAVE overloaded it constantly. Are you guys noticing the belt shift thing more these days?