Well the drivers side of the bed actually sits about 1.5-2" below the passenger side box. The leaf springs are sagging pretty bad and the only reason that I can get from anyone for this would be because the gas tank is on that side.

I was quoted $150 to remove the spring, restring it, and add an extra leaf to hold it together, then put it back on and make it level. But the truck's for sale and it doesn't effect the functionality, so I don't feel liike dumping themoney into it