I would top it off in my truck and go. i have seen redneck swiming pools (a tarp in the bed full of water) and never seen them hurt the truck. that has to be alot more water than the cube.

 

First off, thanks to everyone for the input. The next time I need to haul water, I will try filling it to the top while keeping an eye on the bump stops and general appearance of the load on the truck. It would certainly be to my advantage to fill the thing completely, and bluegrass - you are very correct with the physics of the sloshing. I agree. I mean, weight shift has brought properly loaded airplanes out of the sky!

Here's a quick picture of my set up - this was last fall and I had the tank at the back of the box but now have it moved up to the front for better weight distribution. You get the idea!

 

I'll give you my 2 cents. I have an 03 with 5.4 and 3.73 's super crew. I have hauled one in the bed while pulling 3 on a 12 foot trailor with no problems. Truck still had plenty of power and had no issues with stopping do have a trailor brake

 

Water is actually 8.32lb/gal

Wayne

 

This alludes to a wise compromise. If you have access to a trailer, you would likely be safer putting the cube on a trailer and towing it.

 

Ihave hauled a full pallet of concrete bricks before, that was stock, it did it easy, was riding gently on the bumpstops the entire way home.