[mattpopp]

What is the right way to go about this? I have a 40gal tank I would love to put in the bed but I have no clue on what is the correct way to tie the aux tank into the stock tank. I know you tie it into the filler neck but do you just tie a line directly in? Will the Aux tank just keep the stock tank full until the aux tank is empty? Do you have to worry about over filling the stock tank? Or does there need to be a valve added inline? Like a 12v solenoid to control the aux tank.

 

[JSchuricht]

You are getting auxiliary and transfer tanks confused. An auxiliary tank is a second tank that you switch to with a valve. A transfer tank transfers fuel to another tank either with a filler like you see at the gas station or automatically through the filler neck for instance. Personally I prefer a auxiliary tank with a valve. I can run off either tank, transfer fuel between tanks for maintenance or run different fuels and the tank that isn't in use is shut off so no fuel can escape. Also with a auxiliary setup I use the stock fuel gauge for both tanks, it just reads whatever tank I have selected. A transfer tank setup automatically fills the main tank from a T in the filler neck. You would need a check valve in case of a rollover. Under normal circumstances you wouldn't over fill the stock tank but if the cap were left off it could happen.

 

[mattpopp]

So if I just tie into the filler neck the Truck tank would never over flow? I thought there was a vent or two on the stock tank. Regardless if the fuel cap was on or not. If I am reading you correctly, the Stock fuel tank is completely sealed with the fuel cap on?

 

[JSchuricht]

There are vents but when working correctly only air will escape.

 

[MDarrough]

I did a 100 gal in-bed tank on my '99 SD. I actually built the tank and put a threaded bung on the side of the tank near the bottom. Then threaded a short nipple and ball valve into the bung. Then a 90 deg elbow pointing down. I drilled a hole in the bed and stuck the pipe thru to under the bed. I removed the hose that goes from the filler neck to the oem tank, and attached it to the nipple coming from the in-bed tank.

I would fill only the in-bed tank and open the ball valve to fill the oem tank. When the oem tank was full, I closed the ball valve to prevent any problems.

Mark

 

[jesilvas]

RDS Diesel Install Kit for Auxiliary Diesel Fuel Tank — Fits 1999–Current Ford and Dodge, and 2011–Current Chevrolet and GMC Trucks, Model# 011025 | Auxiliary-Transfer Tank Accessories| Northern Tool + Equipment
I'd use this. Looked for a long time and this is the best I've found.