Auxiliary Fuel Tank Install

by | Apr 18, 2023 | BLOG, Truck and RV, VIDEO

Why an Auxiliary Fuel Tank

When I set out to configure and purchase our truck that we would use to pull our 19,000-pound 5th wheel, I made the mistake of ordering the truck with its standard 32-gallon fuel tank.  I am not sure why I didn’t opt for the 51-gallon tank, as it was only $250 more, and when spending over $80,000 for the truck it certainly wasn’t a matter of cost.  I think the concern that stopped me from going with the larger tank was the additional weight of carrying so much fuel.  Well, as it turns out that was just a silly newbie mistake. As it turns out range, in this case, was the bigger concern – as I found out from the bouts of range anxiety we had as we traveled from New Hampshire to Florida.

I decided that I would investigate swapping out the 32-gallon standard tank for the OEM 51-gallon tank, so I contacted a couple of dealers.  What I found was that the dealers were not able to guarantee that the tank they would order would be the correct one, and that if it was not the correct one, I would still be responsible for the cost and I would not be able to return it or get credit towards the correct tank.  I know, that’s weird and wrong, but two dealers told me the same exact thing.  Rather than taking any chances with all of that I decided to look at other options. Having both a need for additional fuel capacity and additional secure storage for some tools, I started looking for an in-bed auxiliary fuel tank with a toolbox.

After some online searching, I stumbled upon RDS Manufacturing, a company that offers a variety of stand-alone tanks as well as combination tanks and toolboxes.
RDS is in Perry, Florida and coincidentally we would be staying at an RV Resort only 40 minutes from Perry, so I looked for a dealer that could arrange for me to pick the tank up at the RDS factory.

RDS does not sell direct to retail customers, so I had to find a dealer or distributor that was willing to set up the will-call deal and have a reasonable price.  After a few calls I found Tank and Barrel and they were able to set the deal up very conveniently and affordably.   I was able to save on shipping as well as tax.  I highly recommend Tank and Barrel if you are considering getting a tank for yourself.  I’ve put their information below.

The Tank I Chose and Why

The option I went with is the combination 40-gallon tank with a 10-inch-deep toolbox.  I chose this one for several different reasons:

·      The capacity would give me potentially 400 miles of additional loaded range.
·      The toolbox is deep enough to be practical for my needs.
·      Total height is just under 19” (Is below the bedrail)


The installation is straightforward. Some installations may require a few variations, but these are the general steps.

1.         Install the T-Adapter Filler Neck Adapter.
2.         Dry fit the tank in the bed to and confirm clearances for bolts, fuel line, etc.
3.         Drill hole in the bed for the fuel line.
4.         Drill holes in the tank mounting tabs (There are usually 3).
5.         Drill holes for the mounting bolts (Again, there are usually 3).
6.         Install valve on the tank.
7.         Place neoprene between tank and truck bed.
8.         Place the tank and secure it with the provided bolt/spring sets.
9.         Run and attach the provided fuel line.
10.      Fill the tank to about ¼ to ½ and test for leaks and operation.


Here are a few things that I did not cover in the video.

I shopped around for the tank and found that Tank and Barrel was the best option for me.  It was available on Amazon, and I have provided a link below for you to check the price but when I checked it was at least a few hundred more than Tank and Barrel.

I also checked Northern Tool, but they would not ship to store or arrange for a will-call at the manufacturer or distributor so that would have added a few hundred dollars in shipping.

When you order the tank, you’ll need to get the installation kit for your specific vehicle. It comes with the fuel line, fuel hose (like this), the T-Adapter and the necessary hose clamps.  It will generally set you back about $100.  Other than that, everything else you need to install the tank including the valve, bolts and neoprene are included with the tank.

My total cost was $1090 before tax and shipping, which I avoided by picking up at the factory on my commercial account.

As far as the install itself…. I think it was easy if you have all the appropriate tools at the ready.  If I can do it, anyone can so long as you plan properly, take your time, and pay attention to what you are doing.

It took me about 4-5 hours for the complete installation, and that probably could have been quicker, but I spread the project over a few days due to weather and work.
I’m pleased with the quality of the product itself and the service I received from both Tank and Barrel as well as RDS.

If you have any questions, or recommendations on what I could have or should have done differently, comment on the video on YouTube.

Thanks for reading.