If its a dump trailer, the trailer itself weighs alot. United rentals wouldn't even rent one to my friend with a 1500, he had to call me so I could rent it with my F350. He tried to return it and his 1500 and the trailer was dragging cause the truck sagged so much, I had to return it as well.

 

A yard does equal 3000 lbs give or take a few. In the back of the truck it gets as low as possible (minimal bounce jumping on bumper).

As for the dump trailer.. it's heavy even empty. Adding a few yards on top gets critical.