I never used my Blazers much for hauling,but my pickups have been overloaded many times..my old '77 K2500 had a flatbed I made from 4" channel iron pallet racking,they had a beam every 11",the bed alone weighed 900 lbs!..I put a small crane hoist on it with a 1500 lb winch,and I used to haul all kinds of stuff for people,delivered engines and parts for junkyards,etc....one day a friend at one junkyard wanted to scrap a huge 6 cylinder Detroit Diesel from an old Allis-Chalmers bulldozer--his 1700 Trojan forkloader had difficulty picking the engine up,and when he lowered it into my trucks bed carefully,it pushed right thru the plywood decking!

...I made it to the scrapyard 3 miles away OK,when I got the thing unloaded and weighed,I found I had 4,250 lbs on my truck!..the cab and bed were slamming together all the way there,and I felt the floor moving too,the cab had been all patched up ...
On my way back to the junkyard,I had to make a real sharp turn,almost a U-turn,and when I went to turn the steering wheel,suddenly it broke free and it spun around like nothing was connected,and I ran up onto the front lawn of a guys home thats right there that I knew!--the darn rag joint had ripped apart,if that thing had broke with the load in the bed,I would not be here to type this probably!..

...I thought the cab was going to come off the truck when the guy used the electromagnet crane to pick up the engine at the scrapyard,and evidently it did move far enough to rip the rag joint apart,it was holding by a thread evidently,and that sharp turn was the breaking point!...glad I wasn't on my way home going 50 on the highway when it failed!..but the rest of the truck held up fine,despite its frame being very thin in spots,and the leafs were so rusted they looked like barnacles were growing on them...
I used to load my '56 3200 Chevy truck to the top of the cab with car & truck batteries,one day I hauled in over 200 of them,back in '78 when they were bringing 5.75 each for a typical car battery--I blew out one back tire about 1/4 mile from the scrapyard entrance,and when I drove over the scales,the other rear tire exploded ,they had to push me off the scale with a loader!..the load weighed nearly 3500 lbs and I got almost 1800 dollars for the batteries!..but I had to climb a mountain of junk vehicles to remove two rims & tires off a '66 GMC at the top of the heap,to put on my truckso I could go home!..it was 90 degrees out and 4:30 PM,the guys were NOT happy it took me an hour to get them off the junker and onto my truck,they had to stay late!...the truck never had any other problems,I just had a hard time keeping tires on it,I overloaded that thing dozens of times..of course,the frames on those old beasts are 3/8" thick steel too,and GOOD steel,not the recycled crap we get now!..