When full the tank sender should read 20 ohms plus/minus 6 ohms.

When empty the tank sender should read 220 ohms plus/minus 6 ohms

If you wish to 'tweak' the gauge to read more or less you can add resistance in series or parallel as needed to put the needle where you want it.

Official Chrysler opinion is that the fuel pump is partially cooled by the liquid gasoline
and especially in summer a minimum amount of fuel should stay in the tank to prevent
pump motor failure or shorter life.

Regular cabs have 36 gallon tanks
Short bed & Quad Cabs typically have the small 26 gallon tank
except for Cummins/V10 models that have a special 34 gallon tank
that is a different shape than the 36 gallon tank.

 

Something that many people don't realize is that every gas station pump is different. If your filling a tank that is 26 gallons when the low fuel light comes on, then you can guess-timate that there is at least 5 gallons in the tank. So that leaves 21 gallons left. Most pumps stop a few gallons short of being full, so that is does not spill out onto the ground. So 19 gallons is not a bad number. When I fill my truck, I drive until the DTE says '0 DTE' and the pump usually stops at 24 gallons. Then if I sit and pump it longer, I can usually get near 27.5 gallons in the tank. And I'd assume there is still 2+ gallons in the tank anyway, because I was able to drive to the station with the fuel sloshing around while driving. If you really want to see how much fuel the tank will hold then take it out of the truck, empty it out, then fill it up with gas cans, then you'll see how much it will hold. The guy above that mention the reserve, and a capacity near 28... thats probably a pretty accurate number, since I've put in over 27 gallons many times. Thats just my $.02

Almost forgot to mention, when I fill my tank, there is no way to put anymore gas in the system because the gas is sitting just under the gas cap. Meaning that the entire fill tube is holding gas. Remember in "Days of Thunder" when he was building the car he said "I'm gonna give you an extra wide fill tube to give an extra gallon of gas.." (or something like that). It's true, thats where I get my extra capacity.

 

You have a 26 gallon tank if its a short bed. If you have the long bed, the 34 gallon was an option, I believe. There is no 20 gallon tank.

 

Just FYI, my truck is still new enough that the sticker with the part number on the back of the tank. The sticker also says "26 gal"

 

i have the 26gal tank and when my light comes on it takes 24gal to fill up. Is there any way to tell when it hits the reserve?