This is true, and from what I gather not very common knowledge for some reason. I know alot of people who are always running around on empty. However they're the same ******** that need someone to pick them up cause they ran out of gas, and aren't aware that you're suppose to change oil, but are just suppose to put more in when it gets low.
How hard would it be to just fill up your tank and then top it off everyday if you just wanna put 5 and 10 dollars in at a time? You're still gonna end up spending the same amount of money... (sorry this is a personal rant. It's not directed at anyone on here)

 

I completely agree. I let mine get to 3/8, at worse 1/4, before I go fill up. During the winter, I never let it go below 1/2 tank around town. Never know when you'll need to run out and pull a friend out of the ditch, or get stuck yourself and half to let the truck idle for a long time waiting for someone or for you to dig yourself out with a shovel/sand.

My wife just today, for example, let her Jeep get down to 22 miles until empty (overhead). The gauge was on E, and we put 16.6 gallons in (20.5 gallon tank). It wasn't as bad as I thought, but close enough. I would scold her if I knew it'd do any good, but with cars and electronics she just doesn't retain very much that I tell her. Mainly because she's a RN and doesn't have much interest in the specifics of those two categories.

As far as the size of your gas tank, Miami Son, the original was 34 gallons. All 2500 short bed models got the 34 gallon tank, all long bed models (1500/2500/3500) got 35 gallon tanks, and all 1500 short bed models got 26 gallon tanks.

It is very possible, like others have suggested, that it was damaged at some point and a previous owner replaced it with the cheaper 26 gallon tank.