adding transfer tank

RDS will make custom tanks at a reasonable price. I had one made to fit around my Rtrax cover.

Buddy of mine has a ATTA Tank, 80 gals for his short bed LML. Its wired up so he can turn it on, off, or auto. Auto keeps the factory tank between 1/4 and 3/4 full. He also has a mounted on his dash for fuel level in the tank. Paid about $1800 for it installed though. No gauge issues and he burns though a few tanks a week sometimes.

I am not sure on the fords, but for the GMs you can get a Titian Tank. They fit in the stock location, and are much larger. I would go from a 34 gal to a 62 gal on mine.

I use a transfer flow, 75 gallon . Just fill both tanks and drive for ever it seems. No valves to mess with just fill and drive.

I have a 2013 F350 diesel. I also just had an RDS tank installed in the bed yesterday. The fuel line from the aux tank ties into the main filler tube and has an in-line check valve that closes when it senses the fuel level has risen up to the 'cut-in' point in the OEM main filler line. There is also a manual shutoff valve where the line exits the aux tank. This is a gravity feed system.
I have read that leaving the valve open while driving can sometimes confuse the computer, so I intend to run with it closed until the main tank is near empty, then open the valve while at lunch, rest stop, etc. and let gravity do it's thing. I got the 40 gallon/tool box model so now I have 78 gallons available. This tank has it's own vent and because there is an integral toolbox, there is also a locking cover that also locks down over the fill cap, vent, and fuel gauge and keeps everything out of the weather. Also, it is lower then the top of the bed rails, so I can fit some form of a tonneau cover - I hope.

* If you decide to go with an RDS tank, I suggest you also get the $80 install kit. It contains everything you need to tie into the main OEM fill line, including the check valve. Northern Tool has good prices.

Go to northern Hyds. site look at RDS Aux tanks and install kit. Added 45 Gal tank with 12volt valve ,turn on when you want extra fuel turn off when tank shows full, NO Problems Works great!!

I'm sure it has to do with the in tank pump but why can't you use the same system that Ford had with their dual tank trucks :h ? Both my 1990 and 1992 F-150's had dual tanks that all you did was flip a switch on the dash. The only down side was it had fillers on both sides on the truck.

I thought you could now longer use gravity feed tanks? The two main reasons being if a fuel is cut they will empty out, and they also can over fill the main tank. Now if the fill tube is installed into the main tank say three inches in that would keep it from over filling. But if the fill line is taped into the filler neck that will cause issues.

I know on any vehicle that uses a return flow system you should never fill your tank to the top or into the filler tube. I cost us over $800 in repairs on the DD VovloS-80. Seems the e-vac system became over saturated with raw fuel and had to be replaced.

Something else to think about is the return line coming from the injectors will always return to the main tank so my idea of using a switch just got a lot more complicated. You would need some way to return the fuel to the tank it cam from. that means more valves a more cost, I'm beginning to see why these tanks cost so much! I bet the oversize replacement tank/tanks Transfer Flow sells are going to be the best solution for you. Link

Good luck OP

My Ford dealer installed my RDS 90 gallon tank into my 2011 F450. It gravity feeds right into the fill-up tube and pours directly into the main tank. Between the two tanks, I can get 125 gallons. There is also a ball valve cutoff where the pipe leaves the RDS tank.

I have heard some people mention the gauge issue. But so far, mine has caused no problems. The computer will try to lower the numbers on the "miles to empty" reading but after awhile, it gives up and automatically resets itself. I can be driving along and it will say around "220 miles to empty". Then the next time I look down, it will say something like "310 miles to empty".

Only when the auxillary tank empties will things work like normal. But for hundreds of miles, it just reads full.

Get the ball valve though. The only issue I've had is sometimes when the truck sits for awhile and the RDS is full, fuel will work its way through the vent lines and then I'll have a diesel stain on the ground. If I turn the fuel off from the RDS, no problems at all.

http://www.transferflow.com/

They also make replacement tanks LINK if I were looking I think this is the way I would go.

Don

2011 ford f350 cc 6.7diesel auto with air bags.2011 bc3250ts gvwr14000 hitch wt 1920

What we need is more information, truck year, make and model. Along with the same info for the trailer. Payload will be the deciding factor.

Don