Transfer Flow 40 Gallon In-Bed Auxiliary Diesel Fuel Tank System - TRAX 4 (0800116637)

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Regular price $2,180.37
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Transfer Flow 40 Gallon In-Bed Auxiliary (0800116637)

This 40-gallon in-bed auxiliary fuel tank system is a versatile and reliable fuel solution compatible with almost any diesel truck, providing a hassle-free and efficient fuel transfer experience.

Specifications and Design

The fuel tank, rectangular in shape and having a capacity of 40 gallons, is made from 14-gauge ReliaSteel, high-yield aluminized steel, ensuring superior durability and strength. With dimensions of 48 inches in length, 19 inches in width, and 19-3/8 inches in height, the design is compact enough to fit under most standard tonneau bed covers.

Additional Features

The system includes a computer-controlled TRAX 4™ operating system that enables worry-free automatic fuel transfers. Robot-welded seams provide additional strength, making this system more robust than rotationally molded plastic tanks or other steel brands. It also includes all the components needed for installation.

Benefits and Applications

This system is designed to be compatible with almost any diesel truck, including half-ton pickups, trucks with utility beds, Ram Box equipped trucks, or those with a factory installed 5th wheel prep package or other 5th wheel hitch. This nearly universal compatibility makes it a preferred choice for drivers requiring additional fuel capacity but maintaining a small footprint to maximize available bed space. Moreover, the patented fuel tank design and computer-controlled automatic fuel transfers provide a safer and more reliable operation than gravity-fed systems.

Transfer Flow 40 Gallon In-Bed Auxiliary Attributes

  • DOT Approved: DOT Approved For Direct Feed Into OEM Fuel Tank
  • Tank Capacity: 40 Gallon
  • Fuel Type: Diesel
  • Shape: Rectangular
  • Tank Length (IN): 48 Inch
  • Tank Width (IN): 19 Inch
  • Tank Height (IN): 19-3/8 Inch
  • Tool Box Type: No Tool Box
  • Tool Box Length (IN): No Tool Box
  • Tool Box Width (IN): No Tool Box
  • Tool Box Height (IN): No Tool Box
  • Finish: Powder Coated
  • Color: Black
  • Material: Aluminized Steel
  • With Locking Cap: Yes

Offering a 6-year or unlimited-mile warranty, the Transfer Flow 40 Gallon In-Bed Auxiliary system demonstrates confidence in its quality and longevity. With its unique design and superior materials, this system provides an efficient, reliable, and secure solution for your fueling needs, while also being made in the USA.


If you prefer not to use our TRAX 4™ app with your auxiliary tank but still want to know how much fuel you have, Transfer Flow offers an in-cab fuel level monitor LCD. This item is sold separately.

40 Gal
Installation Type
Aluminized Steel
48 in
19 in
19.38 in
Powder Coat Black
ltl shipping
132 lb
Locking Type
Locking Cap
Liquid Type
Transfer Flow Logo

    TRAX 4™

    Want to know the status of your on-board fuel systems? Simply download the TRAX 4™ app to your smartphone and enter your vehicle and fuel system information. In no time, you’ll be able to monitor your pickup’s fuel capacity!
    App Install Details
  • Unlimited Mile


    Transfer Flow fuel systems and parts are covered by a six-year unlimited mile warranty against defects in material and workmanship throughout the U.S. and Canada from the unit purchase date by the original purchaser for the original vehicle the unit was installed in.
  • Need Help?

    Fuel Tank Installers

    Transfer Flow has built an extensive network of 196 authorized installers throughout North America, all of which undergo thorough screening and have demonstrated the ability to install multiple fuel systems from each of our main product lines.
    Installer Map
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Toolbox & Tanks

Discover the unbeatable versatility and reliability of our all-in-one auxiliary fuel tank and tool box combo, where convenience meets practicality in perfect harmony.

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