Have to keep in mind if you have a screw or scab.
I tow ~6,500 lbs relatively regularly towing my drag HD truck to the track. I have towed as much as 10,000 lbs with another 1,500 lbs of payload in the truck. It was REALLY pushing things, I had 18,000 lbs rolling down the highway lol. I had to take the fenders off the trailer because I was over double the payload capacity of the trailer and the tires were rubbing the fenders. I wouldn't recommend doing it, but I was an hour from home and couldn't turn down the deal on the pavers for our patio. Truck actually stopped and accelerated fine, it was just riding on the bumpstops lol. I was more nervous for my trailer than I was for the truck! 8k+ lbs on a trailer meant for 4500 lol.
Pic of my usual load, and few pics of the 10k lb load with ~1,500 lbs in the truck