I am currently pulling a 35ft TT with my '15 F250 6.7 CCSB. I am thinking of upgrading to a fifth wheel but am looking for some advice on a couple of issues.
1st - I realized quickly that the 25 gal stock tank is just too small... I am looking at a Titan 50 gal or possibly an in bed aux tank, 30 gal or so. Any good points or bad for either?
2nd - when I get the fifth wheel hitch, is an in bed aux tank going to be a problem with a short bed.
3rd - if I get the aux tank is a gravity feed ok or should it be pumped from one to the other?
4rd - if I get the titan tank is there going to be an issue getting the 5th wheel hitch installed?
Opinions much appreciated

 

I pulled a 5th wheel for many years with a short bed. I don't know how much room you will have for the auxillary tank. It may be a matter of just measuring and deciding based on the measurements. As far as the tank goes, if you decide on an in bed tank, I am using the RDS 60 gallon tool box combo. Just go to RDS and look at all the different sizes and models. I installed it, https://www.ford-trucks.com/forums/1...k-install.html, and I prefer the gravity flow. It is simple and there is nothing to break down or malfunction. I couldn't be happier with the tank. I know what it is like stopping every 175 miles for fuel when you have that 25 gallon tank. Now I don't need to stop until 700-800 miles while towing. Good luck.

 

I've always had long beds but I think you're better off with an under bed tank, there not much room on top for an in bed type....could be wrong. Personally I have no desire to drive 700 miles at one stetch but I can see how an rv hauler might.

 

I installed an ATTA 45RBR in the bed of my truck that sits below the bed rails at the highest point. This gives me 75 gallons of fuel and allows me to stop where and when I want instead of where and when I have to. It worked great during a 8500 mile trip from GA to Seattle and back towing a 30 ft travel trailer this past summer. This gives me up to 1400 miles unloaded and 700 miles roughly loaded.

It should not be a problem as long as you stick to the measurements and triple check. My tank is a good 1.5 feet in front of the 5th wheel rails and leave plenty of space.

Check into the ATTA solution that provides everything you need. I bought the push n fuel option which puts a momentary switch and gauge in the cab of the truck. When the switch is activated there is a pump that pulls fuel up through a sending unit and into the OEM tank. It works great and it is a great feeling to be rolling down the highway and watch the fuel gauge rise.

I didn't want to get a under the truck tank because if/when I change trucks sometime in the next 30 years, I can take the tank and pieces with me.

I know this is not the same truck as you, but in the link below are some pictures of the install and finished product.

https://www.ford-trucks.com/forums/1...ne-almost.html

Here is the link to ATTA. Great people to deal with and a very sturdy built tank. If you want something custom done to it, just call them up because the tanks are built to order. I wanted the fill spout moved to as far toward the rear of the vehicle is possible, and they did it without hesitation. The welds are strong and clean. No slag in the tank and all wires, connectors and everything was included in the kit.

Aluminum Auxiliary Truck Diesel fuel tanks - Aluminum Tanks and Tank Accessories

 

There is now way I could drive that long without stopping either. I still do normal stops at rest areas and to eat, I just don't have to look for fuel until I unhook for the night. Sometimes I don't even need to look for fuel during the entire trip if I'm not going too far from home. It just makes it easier than trying to match a fuel stop with a meal stop every time.

 

I think a very important consideration with a short bed & adding a aux. fuel tank is weight. I currently have another brand SRW truck, ( have a '16 Lariat on order ) when on a truck stop scale with the 5th wheel discovered the rear axel to be 400lbs overloaded, & I don't have an aux. fuel tank. An aux. fuel tank will add lots of weight to a SRW truck, axle & tires.
John

 

That is a great point. My tank weighs 147lbs empty. Add about 7lbs per gallon for fuel plus some junk in the box and I'm carrying around 600lbs extra. It normally isn't a problem with the newer duallies but it will be with an F250 pulling a 5th wheel with a hitch weight of 2,000lb or more. I haven't researched the capabilities of the new F250, but if I were looking at 5th wheels I would do the math. Whatever you do, don't let the salesman tell you "it will tow anything". Normally they don't know squat about your truck.

 

The ATTA tank I purchased does not weigh that much because it is aluminum. Even if I got 45 gallons into it, it would only be around 350 lbs total for 45 gallons of fuel and the tank. I see this as a good trade off in order to increase my mileage to 700-1400 miles. No one wants to drive 700 miles in one go, but having the ability to pick and choose your fueling spots is priceless when towing a trailer.

It is something to consider, but if done right there should be no problems at all.

 

After I read your post I went back and checked the shipping weight for mine at the RDS site. My tank is aluminum also and weighs 95lbs not 147lbs. I don't know why I remembered it as 147. It is a little heavier because of the toolbox and the hardware I guess. It will take about 52-55 gallons of fuel so that still makes it about 460-500 full of fuel.

 

When I read the 147, I thought well I guess that is a steel box. I did not weigh the ATTA tank, but from what I remember the wooden pallet it came on was heavier than the tank. I picked it up and put it into the bed myself with very little effort and was surprised at the weight.

Being that your tank is larger and holds more fuel, it is easy to add on weight quickly. As I said before, the auxiliary tank for my truck was one of the best if not the best thing I have done to it. It is peace of mind in a box as far as I am concerned.

 

I like the idea of a gravity flow also. My only concern is if there is any issue with a full aux tank and full underbelly tank.
Can fuel come flowing out of the normal filler tube if the tank cap is removed by someone who is just not paying attention...
Do you always fill up the aux tank and just let that feed into the underbelly tank?

 

Ok, I'm not a fully qualified automotive mechanic but I do know which end of the screwdriver to use.
How much was involved in wiring up the fuel pump in the aux tank?

 

Not much wiring at all if you go with the push n fuel version. They have a freedom fuel version as well that monitors your OEM tank level and fills as required. I did not want that option, so I stuck with the momentary switch.

The push n fuel version has a momentary switch that will connect to 12v power of your choice. That is really about it. The wires come color coded and go exactly to where the instructions say which comes as part of the kit. Nothing else needs to be "wired" to the truck other than the power. As for the pump, one ground wire which I attached to the under body of the bed right next to the pump and then the pump has a wire that goes to the switch.

I see a lot of people that run the gravity feed method which is fine and has worked for many years. I wanted positive control of the fuel in the auxiliary tank and wanted it to fill the OEM tank when and where I wanted. I put the switch in the rear of the center console so that I just lift the lid and push it with my right hand going down the road. In about 4-5 miles at 65 MPH it fills about 1/4 of a tank on the OEM. I usually start filling the OEM tank at 1/2 and keep an eye on the auxiliary tank level and fill it when it get down to about 1/8.

You can see from the diagram below it is very simple.

 

Thanks for the wiring diagram. Looks easy enough. Certainly going to give this some thought.
Planning on some extended trips this summer and an aux tank would definitely help with the drive.

 

You will certainly be happier with some extended range with aux fuel, but I would be more concerned with an F-250 vs. F-350 and 5th wheel combo. Our F-250 had no trouble with our vintage canned ham, and I thought it would be easy going to a 5th wheel. But it only took a few times out to realize I was towing at over-max weight for the F-250. The 6.7 wasn't the problem but the rear suspension was. Wrestled with options and ultimately traded for an F-350 dually, and the difference in stability is big.