Hey y'all,

I've been wanting to upgrade my 36.5 gal diesel tank on my 2016 F-350 to the titan 65 gal tank but reading the manual last night, I discovered the chassis cab configuration can come with an additional 40 gal tank behind the rear axle.

I was wondering if anyone here has added one of these to their trucks yet?
http://www.partsgeek.com/gbproducts/...ad=47362750812

To me, having an additional 40gal behind the rear axle would definitely be preferable if it can be done for the same roughly $1600 that the titan tank costs as it gives me an extra 11 gal over the 65 gal tank.

Any thoughts?

Chris

 

I was looking on the Ford Parts website at prices. Granted they are list prices and not what the purchase price at a local dealer might be, but here is what the major parts cost.

Fuel tank - $1614.72
Fuel pump/sending unit - 426.23
Lower skid plate - 364.70
Fuel feed line - $643.32 (no 172" chassis cab model listed, 189, 178, 165, 162 and 141 wheel base)

That does not include other miscellaneous items for installation nor programming the BCM/PCM for two tanks

Granted not cheap are the Titan tanks, but do enjoy the increased capacity of 65 gallons. I can select where I want to refuel using Gas Buddy and not be at the mercy of what ever is available when fuel is needed.

Granted this is not cheap either ($1800) but Titan does have after axle/spare tire tank. But, you then have to decide what to do with your spare.

https://titanfueltanks.com/shop/tita...-ford-4020208/

 

While definitely possible it wont bolt right in. Chassis cab truck have a narrower frame width than the pickups. Might be able to make it work with some custom mounts.

 

The 40 gallon aft axle fuel tank for a chassis cab is just that... for a chassis cab.

While it is true that chassis cabs not only have narrower distanced frame rails, they have wider frame flanges... these frame distinctions are the very least of your concerns, because the pickup frame rails are wider apart, and have narrower flanges, and as such can easily swallow the width of an aft axle chassis cab tank. So tank width is not a problem as far as the frame width difference.

But length is a problem. The distance between the center line of the rear axle and the tail end of the frame is 7.5" shorter on a pick up than it is on a chassis cab. This difference would put the end of the aft axle fuel tank past the vertical plane of the rear license plate mount location on the rear bumper on a pickup, if the aft axle were mounted in such a way as to give the live rear axle pumpkin adequate clearance throughout it's full range of suspension motion, empty and fully loaded, inclusive of an allowance for axle wrap.

However, the length is still the least of your concerns. After all, you can always put short extensions on the frame to move back the bumper a bit, even though it will awkwardly not line up neatly with the bed anymore. And since you're going rouge, you can always shoulder the liability of dismantling the secure 8 bolt factory receiver hitch mounting system that was validated by Ford to SAE testing standards, and jury rig your own receiver hitch mounting system to extend it further aft and off the original frame in order to clear the aft axle fuel tank, all while adding additional leverage to any tongue weight applied, which has the multiplicative effect of reducing hitch capacity and increasing towing stress.

So suppose you've got all that under control. The real problem you will have is quite another matter. How will you rebuild 20% of the cross members to your 2016 truck that is still under the original factory warranty, after you've cut, drilled and chiseled out all the rivets and/or welds of the rear H frame cross member structure that will be in the way of the height of the chassis cab aft axle fuel tank, which on a chassis cab tucks up inside and into the frame to the top frame flange, in order to maintain a decent departure angle so you don't plow the asphalt with the aft axle fuel tank skid plate every time you turn up a driveway?

Will you replace the H frame cross member structure with a flat piece of 1/4" plate bridging across the top of the frame? Then how will you tie the bottom flanges of the frame together, where all the load on the aft spring hangars and shackles is applied to. How will you keep the bottoms of the frame rails from spreading apart?

And where will you anchor the driver's side rear shock absorber? It is staggered aft on the pickups (but not on the chassis cabs) in part to counteract axle wrap. If your plan is to also keep your original midship tank, you can't reverse the shock forward like the passenger side, because your midship tank is in the way. So what will you do?

And then what will you do about the over the axle, under the frame routing of your fluted tailpipe, that is a federally controlled, not supposed to be tampered with part of the emissions system due to the air inlet venting that is used to ameliorate the high exit temperatures of the exhaust during regeneration cycles? The chassis cab tail pipe more or less routes the same direction, but is bent differently, in part to accommodate the aft axle fuel tank.

But let's suppose you're a crack welder, you couldn't care less about emissions laws, and Ford's warranty is meaningless to you. And let's suppose you have a bladder the size of an Olympic swimming pool, lined with steel, so that you can hold it for hours on end while you burn through 75 gallons of fuel capacity on your cobbled together frame with a missing shock absorber and jury rigged receiver hitch. All of that is doable.

Yet the real problem lies ahead, and was already mentioned earlier in this thread. Where are you going to put your spare tire? This is not a trivial concern. I speak from personal experience, having had the aft axle tank which you seek for the last 17 years. With a pick up like utility bed, there is no where to mount the tire that is not in the way of cargo in the bed. I finally got fed up moving the spare around and stopped carrying one regularly. I've had three catastrophic tire blow outs in the truck. And, unfortunately, all three of those instances were times when I wasn't carrying the stupid spare tire that is always in my way.

Fortunately, I have a dually (a chassis cab, in fact), and so on two of those blow out occasions, I've been able to play musical tires on the road side, and single out one or both of the dually pairs in the back in order to substitute the flat on the steer axle and make it home. But on one occasion on a trip headed out of state, I was loaded too heavy to single out a rear pair. I was also too heavy for a flat bed tow truck. That was a very long night into the next day, waiting for someone to drive two hours to come get me, drive two hours to my place where I had a spare, drive two hours back again to deposit me and my spare at the truck on the side of the road with someone else waiting with it to guard the cargo, and then my rescue driver drove two hours back again, as I, now over 8 hours later, am finally back on the road, now that the sun was risen and all the businesses that could have otherwise helped me were finally open.

And you have a SINGLE rear wheel? No extra pair of tires on the back axle? Yeah, that will be your biggest problem, unless you don't use your bed for much. Then you could have some type of rally bar mount for your spare, roasting it in direct sunlight all day as the UV and ozone barbecues and bakes the unexcercised sidewalls.


I hope this brings some reality to your pending project. If it were me, I'd go for a solution that has already been solved by Titan's larger capacity midship tank.

 

Great write up

 

Details .