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Old 04-26-2017, 04:21 PM   #1
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Auxillary Tank In Bed of Truck

Do any of you have a Auxiliary tank in the bed of your truck for fuel? Is so what are you using? Our F450 only has a 38 gal tank and would like to go further between fill ups when traveling. We have a three month trip this summer and don't like the idea of stopping every 300 miles for fuel.

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Old 04-26-2017, 04:41 PM   #2
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No extra tank! When we're traveling we're looking for somewhere to stop in 300 miles, but if I recall you are still working so have limited amount of time. Also have a tool box full of stuff (those combo boxes aren't room enough for my stuff) that I'd lose with the tank & in my opinion I need the toolbox more than another 300-500+ lbs of fuel. If I did see the need for more fuel capacity, I think I'd go with larger replacement for the original tank, doesn't use up bed space.
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Old 04-26-2017, 04:50 PM   #3
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I have the ATTA Freedom Fill system. Works great, fill it and you do not have to deal with it again until its empty.


Freedom Fill Auxiliary System
2015 Ram 3500 SLT Mega Cab DRW, SS Nerf Bars, Andersen Ultimate Hitch, ATTA Freedom Fill System
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Old 04-26-2017, 05:27 PM   #4
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I have a combo tank. Love it. Gives me flexibility and the extra weight isnt enough to be a concern. I've never been able to calculate much, if any, decrease in mileage. And I've never, ever spoken to someone who has an aux tank where it created an issue with mileage.
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Old 04-26-2017, 08:11 PM   #5
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Auxiliary fuel tank

I think an auxiliary tank is a great idea. I've got a 45 gallon aluminum tank mounted to the truck box from RDS and love it. Bought mine from Northern Tool for under $450. It has a 45 degree fill spout making it easier to fill and it included a lockable cap. I decided on a 45 gallon size simply because I could get to anywhere I wanted to in a days drive, without filling up in between, yet at the same time not be so heavy or intrusive in size. There is also a kit to hook up to your fill spout throat on the truck that includes some 3/8" rubber hoses and hardware. Installed the whole thing myself in a couple of hours and put another of ball valve in the 3/8" rubber hose under the box so I could remove the tank and detach it if I needed the whole truck box space. Doesn't take a lot of tools to install, but would recommend removing the back wheel of the truck just to get better access to attach the hoses, etc. when installing. Drilled a couple of holes in the truck box floor, one for directly hooking to the fill hose of the truck, and the other for overflow. I put a rubber grommet around each hole in the floor of the truck, so the metal would not cut or abrade the rubber hoses. I use my complete truck box for other things when not hauling the RW, so I chose to make it somewhat temporary. Every late autumn, just before we head south, I'll reattach the tank and hoses, mount the hitch and we're off. The added weight hasn't really been a problem and I don't think it contributes to any real loss in fuel mileage. It's a gravity feed tank so constantly replenishes the truck tank. Once I start seeing the fuel gauge going down, I know that the accessory tank is empty. Good luck!
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Old 04-26-2017, 09:03 PM   #6
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I've also got the ATTA Freedom Fill 72 gal.system and love it. Never need fuel until we stop for the night. Would not be without it now. We can hold a total of 110 gallons.
This tank is made for the roll up cover and designed to slide under the housing right up to the bed front.

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Old 04-26-2017, 09:25 PM   #7
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I have a Transfer flow 50 gal in the bed of my F450. It has the Trax3 system that monitors and controls the fuel flow, neat feature.

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Old 04-26-2017, 11:14 PM   #8
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I did a very similar install as Woodman. Northern Tool has almost unlimited choices for sizes and tool box combo's. I chose the 60 gal with small toolbox on top. It fits just low enough that I was able to fit my tri-fold over it. It also just clears the handle on the super glide hitch.

It gives me a total of 86 gal now. I like the options of stopping when I find a large enough stop.
Larry, Stephanie Park City, Utah
2017 31SL King, 8K axles, Disc Brakes,17.5 Goodyear H tires,BU Camera,5.5 Onan, Heated HT pads, Two Uniguard Awnings, Slide Toppers, 2000w PSW inverter
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Old 04-27-2017, 05:09 AM   #9
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I have the ATTA combo tank. It fits under the roll top. The freedom fill, fills the tank as I am driving.

This is by far the best functional change I have made. I no longer have to search for fuel where I should not be towing the RW. Every stupid mistake I have made towing was because I was looking for gas. My favorite was a dead end late at night with cars parked every where.

The way I do it know is when the fuel gauge gets to half and doesn't start filling, I start looking for fuel.
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Old 04-27-2017, 03:02 PM   #10
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Thanks for all the information. It is much appreciated

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