Ford Fuel Tank Upgrade For Extended Driving Range

Updated Jan 21, 2015

Transfer Flow replacement fuel tank nearly doubles F250/F-350 Super Duties’ driving range

Landscaper or construction worker, aggregates manager or bridge builder, most owners of heavy-duty pickups in the trades choose a diesel package over gas because it provides the best power for pulling trailers and hauling loads while delivering good fuel economy.

Better fuel economy equates to more time spent in the field and less at the fuel pump.

So the last thing you’d want to see in your new diesel pickup is a smaller fuel tank. But, alas, that’s exactly what’s happened underneath the new Ford Super Duties.

The new engine is said to get about 20-percent better fuel economy than the previous diesel. But instead of extending the driving range of the new trucks, Ford keeps it about the same by cutting the fuel tank size from 30.5-gallons to 26.

That loss in fuel capacity just happens to be by the same amount as the 5.5-gallon Diesel Exhaust Fluid (DEF) reservoir that now sits behind fuel tank on F-250/350Crew Cab 4x4s.

For those who want to stay on the road as long as possible between fuel stops, California-based Transfer Flow has an immediate remedy: Replace the little OEM plastic fuel tank with a 50-gallon steel tank.

It’s an easy upgrade for any shop, as demonstrated by Truck Supply & Outfitters (; 205-553-4203). They installed one of the new fuel tanks, which retail for about $800, in our 2011 F-250 – known affectionately as Project Super Crew.

Professional installer Daniel Parker completed the swap in about 90 minutes. He also shot our Project Super Crew’s new tank with All-Pro Lining’s spray-on protective bed coating to keep it looking good over the long haul.

As you can see from the photos, the fuel tank upgrade is simple and doesn’t require any special tools other than a good transmission jack when using a hoist, or floor jack if a hoist isn’t handy. Transfer Flow’s step-by-step installation instructions are thorough, leaving nothing to chance.

Upgrading to the larger replacement fuel tank nearly doubles driving range, which means less time spent at the fuel pump and more time on the jobsite. That’s a win-win in our book.

Go to the Project Super Crew installs at to view more detailed step-by-step photos.


1 Unbolt the filler neck from the body and remove the fuel tank skid plate. Place a transmission jack under the tank and use cinch straps to secure it to the stand. Then unbolt the fuel tank from the frame and slowly lower it about six inches.

2 Reach on top of the forward section of the tank and carefully disconnect the supply and return lines from the tank. Disconnect the sending unit plug.

3 Slowly and carefully lower the fuel tank and move it to a work area.

4 Transfer Flow’s 50-gallon replacement steel tank is nearly twice the volume of the plastic OEM Ford fuel tank.

5 Remove stock sending unit by tapping the retaining ring counterclockwise with a hammer. Switch the stock float with the one provided by Transfer Flow.

6 Test the new float with the OEM sending unit to ensure proper adjustment. The multimeter should read between 175-185 ohms when the float is at bottom (empty position) and 7-14 ohms when it at the upper stop (full).

7 Place sending unit in TFI tank and rotate lock ring to secure it in place. Indention in tank (arrow) helps proper alignment. Install rollover vent valves.


8 Install supplied TFI steel straps (above), then cut the OEM fuel and vent hoses to correct length and install on new tank.

9 Place TFI tank on transmission jack and lift it into position. Reconnect the fuel lines and electrical plug to the tank fittings and sending unit. Then raise and bolt into place using new straps and frame mounting brackets.

10 Siphon any remaining fuel from the old fuel tank to the new one. We used the Super Siphon hose ($11) from to make the fuel transfer quickly.

11 Transfer Flow’s 50-gallon replacement tank fits nicely under our 2011 F-250, and doesn’t pose any issues with ground clearance.