Amongst all that I have experienced, I don't recall anything as catastrophic as this one:
White Freightliner, tri-axle dump, was sent to work on a site with it, this was really a road truck, 315 cummins and 8 spd with lo hole, 19'-0" long box with 5'-0" sides, you could load 30+ tons of asphalt from the plant into it, truck weighed 33,000 empty.
I back into the pile, excavator loading us out, well when there was an operator, sometimes it was load yourself day. The operator overloaded me for the conditions, haul road was a bit soft, dry but underneath was soft and the trucks were making 2"-4" ruts. About 100 yards or so from the pile, on my way to the fill area, just the other end of the site, as I am going along....... BANG !!!!, what the..... ???? Power divider literally exploded, sent gears right through the case, I still have pieces of both the case and the gears in a jar. Good thing no one was standin nearby. It needed to be towed to the shop, and myself and the mechanic who also drove and ran equipment, repaired it that evening so it was ready to work again, did not go out on that job again.
After it happened, I looked into the box, operator had it spilling out the sides, had I known or saw it first ( the way it was handling I knew something was up, just did not stop in time ) I'd have dumped it off right there in front of the excavator, and had him re-load 2/3 or a bit less than was on there, too much resistance on that haul road, and it found a weakspot. Plenty of breakdowns with trucks, and earthmoving equipment, but this is the only one that exploded, not too bad to repair, owner was not happy, but realized the truck should not have been used on the site, we trailered over an old tandem F-850 ford that was off the road, had a detroit and automatic, the box on this thing was unreal, never saw one raise so fast, not all that big, but much better for this site job. A lot of contractors would use old mack B-models or old DM's, or similar trucks for on site hauling, sending the tri-axle was a mistake.