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Auxiliary Fuel Tank options

tomthyme
Explorer
Explorer
Hey Folks!

We would like to add an auxiliary fuel tank to our F350. We have been looking at the in-bed models from TransferFlow, Titan, etc.

I would like the tank to fit under a tonneau cover.

Do you guys have any experience with these tanks?

We are also looking at the replacement tanks that mount under the truck bed. However, these make me a little nervous with possible road debris causing issues. This version leaves my bed free, which is a big deal.

What do you guys think?

Thanks so much!
2015 F350 King Ranch Dually 4x4, 22k Reese hitch
2011 Carriage Cameo 37cksls
Sarah (most beautiful creature in the world)
Mickey (105lb golden - good thing he's pretty)
Ashlee (85lb lab - spectacular pal)
Dutch (120lb lab - young one in training)
62 REPLIES 62

Slownsy
Explorer
Explorer
Titan offer a shield for ther 50 gallon tank, I have youst instaled one.
Frank.
Frank
2012 F250 XLT
4x4 Super Cab
8' Tray 6.2lt, 3.7 Diff.

laknox
Nomad
Nomad
djgarcia wrote:
Nicholsfamily05 wrote:
djgarcia wrote:
Dave H M wrote:
For the gas experts here, I modified my post to include a general comment on aux gas tanks and then replied to the OP concerning custom made tanks.

:h Both replies to the info on gas aux tanks agree with me that the tanks can and are made for gasoline.

I hesitated to post since it looks like this post is headed for a tangent.


What company sells the auxillary tank for a GAS engine??


Transfer flow has them


The only aux. gas tank they sell requires that you have to pull over and use a nozzle to fill your regular tank.


I guess the regs have changed since the 70's, when I had 2 tanks on my truck from the factory; left and right side. Just flipped a switch to change tanks. Changed the fuel sender, too.

Lyle
2022 GMC Sierra 3500 HD Denali Crew Cab 4x4 Duramax
B&W OEM Companion & Gooseneck Kit
2017 KZ Durango 1500 D277RLT
1936 John Deere Model A
International Flying Farmers 64 Year Member

minnow
Explorer
Explorer
dirtydan57 wrote:
I thought I read where replacement tanks protrude below the frame rails. If that is true, wouldn't that potentially be an issue taking a truck off road?


Some do, some don't. Depends on the truck. Some tanks are made longer and don't hang any lower than the OE tank. Also one manufacturer I know of offers a shield kit for their tank.

McIntraveler
Explorer
Explorer
I thought I read where replacement tanks protrude below the frame rails. If that is true, wouldn't that potentially be an issue taking a truck off road?
2016 Grand Design 317RST
2016 Ram Laramie 4x4, CC, LB, DRW, CTD, AISIN, 3.42.

edatlanta
Explorer
Explorer
laknox wrote:
tomthyme wrote:
Hey Folks!

We would like to add an auxiliary fuel tank to our F350. We have been looking at the in-bed models from TransferFlow, Titan, etc.

I would like the tank to fit under a tonneau cover.

Do you guys have any experience with these tanks?

We are also looking at the replacement tanks that mount under the truck bed. However, these make me a little nervous with possible road debris causing issues. This version leaves my bed free, which is a big deal.

What do you guys think?

Thanks so much!


Why would an under-bed tank make you nervous? All the Big 3 use plastic tanks and I'd bet that the after-market versions are a heavier gauge plastic than the OEM tanks are.

Lyle


My OEM tank was plastic. The replacement Titan is approximately double the weight of the OEM. I made this replacement a number of years ago and don't remember the exact weight, but the Titan is much more substantial.
Ed
KM4STL

2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch, Progressive Industries EMS-PT50C, TST Systems 507 TPMS
2010 Jayco Designer 35RLTS,Cummins/Onan RV QG 5500 EVAP
Fulltime since 2010

GoPackGo
Explorer
Explorer
I just looked at the CW site. Looked for 'auxiliary fuel tanks'. They have a sale on all their RDS tanks. 60 gallon combo tank is $743 + freight ($150). Install kit not included. You should compare to Northern Tools prices to see if that's a good deal.

Would the freight charge disappear if it was shipped to a CW store ?

Imaroadrunnr
Explorer
Explorer
Greetings,
I got an ad from Camping World (Mecca to many f us) and they have a special on a combo auxiliary tank and tool box with a free install kit for a measly $731.97. The ad does not mention the manufacturer or the capacity so if this is at least a 40 gallon tank do you knowledgeable folks think this is a good price? One thing not mentioned is if you use an electric fuel pump, use a pump made for diesel fuel as the diesel fuel will screw up a gasoline pump. We are going to head to Florida and then up the coast to Maine and then back to Las Vegas soon if I ever get over the shingles that I've had for over a week. Ouch!
Stan Mitchell
Las Vegas
'o5 Ram CTD 6 speed 3500 w/ 59k miles. Cream Puff
Yes I am a RoadRunner

MarkTwain
Explorer
Explorer
Nicholsfamily05 wrote:
djgarcia wrote:
Dave H M wrote:
For the gas experts here, I modified my post to include a general comment on aux gas tanks and then replied to the OP concerning custom made tanks.

:h Both replies to the info on gas aux tanks agree with me that the tanks can and are made for gasoline.

I hesitated to post since it looks like this post is headed for a tangent.


What company sells the auxillary tank for a GAS engine??


Transfer flow has them


The only aux. gas tank they sell requires that you have to pull over and use a nozzle to fill your regular tank.

laknox
Nomad
Nomad
tomthyme wrote:
Hey Folks!

We would like to add an auxiliary fuel tank to our F350. We have been looking at the in-bed models from TransferFlow, Titan, etc.

I would like the tank to fit under a tonneau cover.

Do you guys have any experience with these tanks?

We are also looking at the replacement tanks that mount under the truck bed. However, these make me a little nervous with possible road debris causing issues. This version leaves my bed free, which is a big deal.

What do you guys think?

Thanks so much!


Why would an under-bed tank make you nervous? All the Big 3 use plastic tanks and I'd bet that the after-market versions are a heavier gauge plastic than the OEM tanks are.

Lyle
2022 GMC Sierra 3500 HD Denali Crew Cab 4x4 Duramax
B&W OEM Companion & Gooseneck Kit
2017 KZ Durango 1500 D277RLT
1936 John Deere Model A
International Flying Farmers 64 Year Member

dapperdan
Explorer
Explorer
backlater wrote:
On the gravity feed tanks, how long does it take to fill the factory tank back up?


If my truck tank is almost empty it can take a couple of hours to refill the truck tank. I never really timed it though, usually when I see we're running low I flip the valve when we get to the next stop.

Dan

railroadpastor
Explorer
Explorer
I have a 50 gallon tank in my 5er. I got it at Northern equipment. It has a small tool box on the top of it. It is just below the bed rail.
When we traveled to Alaska we really needed it. I have it hooked up to an inline fuel pump and I can pump the gas from it to my main tank as I travel down the road.

ACZL
Explorer
Explorer
Switched out stock 29 gallon tank for T-flow 50 gallon. It's made of aluminized steel and had their protective coating sprayed on it at T-flow. Weighs about 70-80 lbs. As AP said, "it's a heavy cuss", but am very happy w/ it. Having a SB to boot, it's nice to use the full bed of box. IMO, I don't feel it's a low as GM's DEF tank.
2017 F350 DRW XLT, CC, 4x4, 6.7
2018 Big Country 3560 SS
"The best part of RVing and Snowmobiling is spending time with family and friends"
"Catin' in the Winter"

GoPackGo
Explorer
Explorer
jcain wrote:
GoPackGo wrote:
I have an RDS 40 gallon tank combo/toolbox in my F350 and it sits completely under my tonneau cover. This is a nice, simple, cheaper then other alternatives, addition that I have been using since I started fulltiming in Jan '14. It has worked flawlessly. And it's not terribly difficult to flip that on/off lever when I want to fill the main tank. I now carry about 78 gallons of diesel fuel.

It has a built-in fuel gage for the tank. Included with the install kit is an auto-shutoff to be used where the aux tank fuel line splices into the main OEM fuel filler hose. This prevents fuel from backing up the OEM line and overflowing out the fuel filler door.

RDS makes many different sizes and shapes of tanks - take a look at their website. Northern Tool carries them.

Great peace of mind.


Have a model number and picture by chance?


From the RDS site - It is model # 72775. It's 19 inches tall, which is about an inch shorter then my bed rails.

If I was to do it again, I would get Model # 72743. That is a 60 gallon model with a smaller toolbox. But the exterior dimensions (including height of 19 inches) are exactly the same as the 40 gallon model. I don't carry too much in the toolbox so I'd rather have the extra fuel capacity.

GoPackGo
Explorer
Explorer
backlater wrote:
On the gravity feed tanks, how long does it take to fill the factory tank back up?


It is very slow. The small line (3/8 ?) flows more fuel then the engine consumes when towing, so there is no problem in that regard. Your in-cabin fuel gauge will definitely move towards the Full mark.

I generally flip the lever on mine when I get down to 1/4 tank or just let it run overnight.

jcain
Explorer
Explorer
GoPackGo wrote:
I have an RDS 40 gallon tank combo/toolbox in my F350 and it sits completely under my tonneau cover. This is a nice, simple, cheaper then other alternatives, addition that I have been using since I started fulltiming in Jan '14. It has worked flawlessly. And it's not terribly difficult to flip that on/off lever when I want to fill the main tank. I now carry about 78 gallons of diesel fuel.

It has a built-in fuel gage for the tank. Included with the install kit is an auto-shutoff to be used where the aux tank fuel line splices into the main OEM fuel filler hose. This prevents fuel from backing up the OEM line and overflowing out the fuel filler door.

RDS makes many different sizes and shapes of tanks - take a look at their website. Northern Tool carries them.

Great peace of mind.


Have a model number and picture by chance?
2014 Avalanche 355rk
2016 F350 CC-DRW Fx4, Tow Boss, Monochromatic King Ranch,Fox 2.0, Pmf Fox 2.0 DSS, OUO ALA, OUO spring thing, OUO traction blocks & bars, AL 5000 ultimate + wireless one, AMP steps,Projectors, Rigid d2 fog lights and 30"sr light bar.