Hi, I have a 2012 F350 short box and pull a fifth wheel. The F350 has a very small fuel tank and im constantly stopping to refuel. Im looking into a auxillary tank. Some are aluminum, some painted steel. Some are listed as just transfer tanks and are much cheaper. The transfer tanks are not recomended for hooking up to fuel fill line.Some have electric pumps and some are gravity fill. Im a bit confused on what is legal for direct hook up to the trucks fill line. I have about 24 inches in front of my hitch. I would like at least a 50 gallon tank. I would like to keep pricing below $700 and keep it as simple as possable. Any suggestions or advice on aluminum vs steel and gravity feed vs electric pump?thanks for any help.Lee.

Gravity fill is ok, if you have an automatically closing valve in the system. A solenoid valve that will close when it looses power. Open gravity flow is illegal in many states.

I have the same truck. When we first went full time and started traveling I really felt the need to keep more fuel on board. I never really had the desire to make my capacity 70 to 80 gallons, but I investigated maybe adding another 25.What it came down to for me was actual need. After the first several months (maybe 5,000 miles) of traveling I discovered that a 200 miles range, or about 3 hours was enough and I really didn't mind stopping for fuel. Actually we have found that we rarely, if ever, have to fuel more than once per day while pulling FW.I have four 5-gallon diesel cans, but generally only carry three of them. They fit nicely in my bed tool box and are easy to pull out and refuel with. Depending on what part of the country we are traveling in, sometimes I have diesel in them and sometimes I don't. The point is, if I need to I can actually leave in the morning towing with as much as 46 gallons for a range of over 400 miles. Total cost of my "auxiliary" fuel supply was about $40.00 and that included aftermarket easy-pour spouts.I know many RVers like the idea of hauling 70 - 100 gallons of fuel down the road. I have considered all the arguments of doing this, like being able to shop around for better diesel prices. But if I am hauling 500 - 700 pounds of extra weight down the road I am going to get less mpg, even though I may have just saved .10 a gallon filling up with that 100 gallons. Yes I have saved $10.00, but if I get 10mpg that day instead of 11mpg because of all that extra fuel weight, then I have used an extra 3 or 4 gallons to drive the same 400 miles. I spent about $15.00 to save $10.00.In my mind if I spent several hundred dollars on an auxiliary tank I had better really need it plus I would want it to pay for itself in a couple of years.

Been thinking about doing the same, here are some options from Camping World.

I'm with C-Bears on this one.Just add a small portable 12 volt pump to the scenario & it couldn't be much easier. :B

I use an RDS 45 gal only 9" out of the bed full width and height. Gravity feed into stock tank is legal go to Northern Tool they have everything you need and about $550 tank install kit and ebay 12 volt valve in feed line from tank. I have 26 gal stock on the truck and 45 gal. aux gives me an easy 600 miles before having to stop for fuel that way we plan our stops to include best price fuel along the way, The tank has paid for its self in 2 yrs.http://www.northerntool.com/shop/tools/product_200306745_200306745http://www.northerntool.com/shop/tools/product_200315501_200315501

Auxiliary fuel tank | Good Sam Community

22 Replies

GoPackGo
Explorer
Feb 26, 2015
wintersun wrote:
Forget about $700 and plan on spending up to twice that amount.

Not hardly.

I just went to the Northern Tools site. They sell the RDS combination 40 gallon aux tank/toolbox that I have for $679. The 60 gallon aux tank/toolbox is $779. It has the same footprint (fits under the rails) but has a smaller toolbox.

A 60 gallon aux tank (no toolbox) is $529.

The gravity feed install kit for these is $70.

Tim
wintersun
Explorer II
Feb 25, 2015
Forget about $700 and plan on spending up to twice that amount. The auxiliary fuel tanks have to be made much stronger than a replacement tank as they are exposed in the bed of the truck.

Titan is one company that makes both OEM replacement tanks with up to 60 gallons of capacity as well as bed mounted tanks.
C-Bears
Explorer
Feb 20, 2015
Fixed Sight Training wrote:
NMDriver wrote:
C-Bears wrote:
I have the same truck. When we first went full time and started traveling I really felt the need to keep more fuel on board. I never really had the desire to make my capacity 70 to 80 gallons, but I investigated maybe adding another 25.

What it came down to for me was actual need. After the first several months (maybe 5,000 miles) of traveling I discovered that a 200 miles range, or about 3 hours was enough and I really didn't mind stopping for fuel. Actually we have found that we rarely, if ever, have to fuel more than once per day while pulling FW.

I have four 5-gallon diesel cans, but generally only carry three of them. They fit nicely in my bed tool box and are easy to pull out and refuel with. Depending on what part of the country we are traveling in, sometimes I have diesel in them and sometimes I don't. The point is, if I need to I can actually leave in the morning towing with as much as 46 gallons for a range of over 400 miles. Total cost of my "auxiliary" fuel supply was about $40.00 and that included aftermarket easy-pour spouts.

I know many RVers like the idea of hauling 70 - 100 gallons of fuel down the road. I have considered all the arguments of doing this, like being able to shop around for better diesel prices. But if I am hauling 500 - 700 pounds of extra weight down the road I am going to get less mpg, even though I may have just saved .10 a gallon filling up with that 100 gallons. Yes I have saved $10.00, but if I get 10mpg that day instead of 11mpg because of all that extra fuel weight, then I have used an extra 3 or 4 gallons to drive the same 400 miles. I spent about $15.00 to save $10.00.

In my mind if I spent several hundred dollars on an auxiliary tank I had better really need it plus I would want it to pay for itself in a couple of years.

Excellent analysis and I agree 100%

With respect your rig is probably well over 20k lbs. I don't think an extra 500 lbs are going to make a 1 mpg difference. Or any measurable difference.

It may or may not drop my MPG by one. I am just guessing that several hundred pounds would decrease my MPG. It would make sense to me that pulling up a grade with an extra 500 pounds would take more fuel, but maybe getting pushed back down the other side with an extra 500 pounds would make it up with better MPG?

I am one of those folks that ended up with a SRW 1-ton and a FW that has me right on my maximum weight limits, mainly on my drive axle. So no matter if I buy into the theory that a heavier unit uses more fuel or not, in my case I sure don't want to add any weight.
Bird_Freak
Explorer II
Feb 19, 2015
I just installed a 60 Gal. RDS tank in my buddys 2015 F-350. Gravity feed and used the kit from Northern Tool. No solenoid's to mess with. Stops flow when fuel comes into filler neck.
Fixed_Sight_Tra
Explorer
Feb 18, 2015
NMDriver wrote:
C-Bears wrote:
I have the same truck. When we first went full time and started traveling I really felt the need to keep more fuel on board. I never really had the desire to make my capacity 70 to 80 gallons, but I investigated maybe adding another 25.

What it came down to for me was actual need. After the first several months (maybe 5,000 miles) of traveling I discovered that a 200 miles range, or about 3 hours was enough and I really didn't mind stopping for fuel. Actually we have found that we rarely, if ever, have to fuel more than once per day while pulling FW.

I have four 5-gallon diesel cans, but generally only carry three of them. They fit nicely in my bed tool box and are easy to pull out and refuel with. Depending on what part of the country we are traveling in, sometimes I have diesel in them and sometimes I don't. The point is, if I need to I can actually leave in the morning towing with as much as 46 gallons for a range of over 400 miles. Total cost of my "auxiliary" fuel supply was about $40.00 and that included aftermarket easy-pour spouts.

I know many RVers like the idea of hauling 70 - 100 gallons of fuel down the road. I have considered all the arguments of doing this, like being able to shop around for better diesel prices. But if I am hauling 500 - 700 pounds of extra weight down the road I am going to get less mpg, even though I may have just saved .10 a gallon filling up with that 100 gallons. Yes I have saved $10.00, but if I get 10mpg that day instead of 11mpg because of all that extra fuel weight, then I have used an extra 3 or 4 gallons to drive the same 400 miles. I spent about $15.00 to save $10.00.

In my mind if I spent several hundred dollars on an auxiliary tank I had better really need it plus I would want it to pay for itself in a couple of years.

Excellent analysis and I agree 100%

With respect your rig is probably well over 20k lbs. I don't think an extra 500 lbs are going to make a 1 mpg difference. Or any measurable difference.
GoPackGo
Explorer
Feb 17, 2015
They are made of the same materials. The difference is that you are expected to attach some sort of pump and nozzle on top of the tank so you can pump fuel into a tractor, etc. It will have a topside fitting for that purpose. You could fit the pump and nozzle and then refuel your own truck if you wanted. It will not have the small fitting near the base of the tank where you would attach the hose that runs down to your OEM fuel line.
schl44
Explorer
Feb 17, 2015
Thanks for all the responses! Is a tank that is only listed as a transfer tank legal to hook up to the fuel fill on a truck. These tanks are much cheaper. Or Is there only purpose to transfer fuel to another piece of equipment? THANKS!!!
WeBeFulltimers
Explorer
Feb 16, 2015
I just purchased from Amazon and installed a 38 gallon DeeZee aux tank with DeeZee gravity feed adapter. Tank is well made of diamond plate aluminum. Looks and works great. Cost just under $500. Truck is 2012 F350 PSD. Ups my towing range to 650 miles which is 2 days for us in most instances.
jnharley
Explorer
Feb 16, 2015
We also change our fuel tank as soon as we purchase a new truck, leaving the bed free. That way, we can drive all day and not have to worry about stopping for fuel. When we arrive at a campground, we disconnect and fuel up. Our large fuel tank was very handy in Alaska this past summer where open fuel stations can be far apart.
qchunter
Explorer
Feb 16, 2015
I bought my truck with a 45 gallon transflo tank. It replaces the factory tank so you don't lose any cargo room in the bed. You don't worry about transferring fuel or fill valves failing. Changing the fuel tank will be my first upgrade to any truck i get. It's even great not having to fill up every week as my truck is my daily driver.

Forum Discussion

Auxiliary fuel tank

22 Replies

About RV Newbies

Related Content

Auxiliary fuel tank

AUXILiARY FUEL TANK

Auxiliary fuel tank?

Auxiliary Fuel Tank options

auxiliary fuel tank