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Questions? Call or Text our US based team: 800-964-5341
Questions? Call or Text our US based team: 800-964-5341

Auxiliary Fuel Tanks for Sale

We offer a full line of Auxiliary Fuel Tanks for sale.  Choose from sizes that start at 30 gallons and increase up to 110 gallons.  We offer a variety of designs including rectangle, L Shaped, wedge, and low profiles.

Auxiliary fuel tanks allow you to transfer diesel fuel directly into your truck's factory gas tank.  We do not sell Gas Auxiliary Fuel Tanks.

Not sure which tank is best for your truck?

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Transfer Flow 75 Gallon Auxiliary Tank
$1,889.76 - $2,177.82
$1,889.76 - $2,177.82
$1,889.76 - $2,177.82
$1,889.76

Transfer Flow In-Bed Auxiliary Fuel Tank System

The Transfer Flow In-Bed auxiliary fuel tank is designed to be compatible with almost any diesel truck, including half-ton pickups, trucks with uti...

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ATI AUX30R auxiliary fuel tank Sale Sale
$675.00 - $776.47
$675.00 - $776.47
$675.00
$573.75 - $660.00
$573.75 - $660.00
$573.75

ATI Rectangular Diesel Aluminum Auxiliary Tank

Aluminum Tank Industries rectangle aluminum auxiliary fuel tank is available in sizes that range from 30 gallons to 55 gallons.  These light weight...

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ATI AUX58R auxiliary fuel tank Sale Sale
$801.47 - $864.71
$801.47 - $864.71
$801.47
$681.25 - $735.00
$681.25 - $735.00
$681.25

ATI Diesel Aluminum Auxiliary Tank

Aluminum Tank Industries rectangle aluminum auxiliary fuel tank is available in sizes that range from 51 gallons to 66 gallons.  These light weight...

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ATTA Diesel Auxiliary Roll-Top Bedcover Tank 45 gallon
$1,145.00 - $1,390.00
$1,145.00 - $1,390.00
$1,145.00 - $1,390.00
$1,145.00

ATTA Diesel Auxiliary Roll-Top Bedcover Tank

  The aluminum ATTA Auxiliary Roll-Top Bedcover Tank is designed to be in conjunction with a roll-top bed cover. The aluminum auxiliary diesel tank...

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ATTA Sleeper Diesel Auxiliary Fuel Tank 110 gallon closeup
$1,741.00 - $1,741.00
$1,741.00
$1,741.00 - $1,741.00
$1,741.00

ATTA Sleeper Diesel Auxiliary Fuel Tank

The aluminum ATTA Sleeper Diesel Auxiliary Fuel Tank is a 110 gallon rectangular aluminum auxiliary fuel tank designed to fit underneath a truck b...

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ATTA Diesel Extreme Wedge Auxiliary Fuel Tank
$1,141.00 - $1,528.00
$1,141.00 - $1,528.00
$1,141.00 - $1,528.00
$1,141.00

ATTA Diesel Extreme Wedge Auxiliary Fuel Tank

ATTA Aluminum Extreme Wedge Style fuel tanks are constructed from .125 gauge aluminum. Wedge Style tanks are designed for full size Dodge, Ford, a...

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Transfer Flow 40 Gallon Under Tonneau Cover Auxiliary Tank
$1,745.26 - $1,870.62
$1,745.26 - $1,870.62
$1,745.26 - $1,870.62
$1,745.26

Transfer Flow Low Profile Under Tonneau Auxiliary Fuel Tank

The low profile Transfer Flow auxiliary fuel tank is designed to fit under tonneau covers.  Choose from 40 or 50 gallon sizes. Either option offers...

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Fuelbox WD85
$1,650.00 - $2,000.00
$1,650.00 - $2,000.00
$1,650.00 - $2,000.00
$1,650.00

The Fuelbox Wedge Auxiliary Fuel Transfer Tank

The Fuelbox Wedge Auxiliary Fuel Transfer Tank is an in bed diesel fuel tank. The wedge tank is designed for flatbed pickups only 65 inches long. *...

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Fuelbox LT70T
$1,650.00 - $2,050.00
$1,650.00 - $2,050.00
$1,650.00 - $2,050.00
$1,650.00

The Fuelbox L Shaped Auxiliary Fuel Transfer Tank

The Fuelbox L-Shaped Auxiliary Fuel Transfer Tank is an in bed diesel fuel tank. Choose whether you want to use this fuel tank as a transfer tank o...

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The Fuelbox FT47 closeup
$1,485.00 - $2,075.00
$1,485.00 - $2,075.00
$1,485.00 - $2,075.00
$1,485.00

The Fuelbox Auxiliary Fuel Transfer Tank

The Fuelbox Auxiliary Fuel Transfer Tank is an in bed diesel fuel tank. Choose whether you want to use this fuel tank as a transfer tank or an auxi...

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ATTA L-Shape Diesel Auxiliary Fuel Tank 90 Gallon
$1,593.00 - $1,652.00
$1,593.00 - $1,652.00
$1,593.00 - $1,652.00
$1,593.00

ATTA L-Shape Diesel Auxiliary Tank

The aluminum ATTA L-Shape auxiliary diesel tank is for long beds only.  It comes standard with duel fill necks for easier fueling. L-Shape tanks w...

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Diesel Auxiliary Under Toolbox Tank 30 Gallon
$1,024.00 - $1,024.00
$1,024.00
$1,024.00 - $1,024.00
$1,024.00

ATTA Diesel Auxiliary Low Profile Under Toolbox Tank

The aluminum ATTA low profile under toolbox fuel tank is designed for short beds only. The Under Toolbox fuel tank is designed to work in conjuncti...

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Diesel Wedge Auxiliary Fuel Tank 50 Gallon
$1,013.00 - $1,343.00
$1,013.00 - $1,343.00
$1,013.00 - $1,343.00
$1,013.00

ATTA Diesel Wedge Auxiliary Fuel Tank

ATTA Aluminum standard wedge tanks give you more of the custom look compared to a standard rectangular tank. The standard wedge auxiliary tank is ...

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$924.00 - $1,494.00
$924.00 - $1,494.00
$924.00 - $1,494.00
$924.00

ATTA Rectangular Diesel Auxiliary Fuel Tank

ATTA rectangular diesel auxiliary fuel tanks are designed with .125 aluminum gage and are available in sizes that range from 40 gallons to 110 gall...

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ATTA Below Bed Rail Diesel Auxiliary Tank 45 gallons
$970.00 - $1,406.00
$970.00 - $1,406.00
$970.00 - $1,406.00
$970.00

ATTA Low Profile Below Bed Rail Diesel Auxiliary Tank

ATTA Low Profile Below Bed Rail rectangular tanks are designed to be used with a hard or soft bed cover. The highest portion of the tank will be b...

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ATI Wedge Auxiliary Fuel Tank AUX60W
Sale Sale
$855.88
$855.88 - $855.88
$855.88
$735.00
$735.00 - $735.00
$735.00

ATI Wedge Auxiliary Fuel Tank

ATI aluminum wedge diesel auxiliary fuel tanks are designed for flatbeds and pickups with a 5th wheel. The tank slopes at a 45 degree angle on the...

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ATI L-Shaped Auxiliary Tank AUX80L
Sale Sale
$855.88
$855.88 - $855.88
$855.88
$803.75
$803.75 - $803.75
$803.75

ATI L-Shaped Auxiliary Fuel Tank

ATI aluminum diesel L-shaped auxiliary fuel tanks are designed to work with a crossover style toolbox or chest box. The bottom of the L-shape fits...

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ATI AUX43R auxiliary fuel tank

Auxiliary Fuel Tank for Truck Bed

ATI's diesel auxiliary tank mounts directly to your truck bed.

Available sizes range from 38 to 46 gallons (ships by UPS).

Use the gravity feed fuel shotz kit to transfer diesel fuel directly to your truck fuel tank.

  • 30 Gallon - 48.5"L x 19"W x 9"H (fits short beds)
  • 41 Gallon - 48.5"L x 11"W x 19"H (fits short beds).
  • 42 Gallon - 48.5"L x 19"W x 12"H (fits short beds with tab modification).
  • 43 Gallon* - 51"L x 12"W x 16.5"H (fits short beds).
  • 46 Gallon - 57"L x 12"W by 16.5"H (fits short beds).

*43 gallon size is notched with a bottom tank length of 51 inches and a top length of 58 inches.

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ATI AUX65R Auxiliary Tank

Gravity Feed Diesel Auxiliary Fuel Tank

ATI offers larger in bed auxiliary tanks with sizes ranging from 51 gallons to 66 gallons.

Transfer diesel fuel using a gravity feed auxiliary fuel kit.

  • 51 gallon* - 55"L x 9"W x 24"H.
  • 58 gallon* - 51"L x 21"W x 13"H.
  • 62 gallon* - 54"L x 21"W x 13"H.
  • 66 gallon - 55"L x 18"W x 17"H.

*51 gallon size has a 55 inch notched bottom length and 60" top length.

*58 gallon size has a 51 inch notched bottom length and 58 inch top length.

*62 gallon size has a 54 inch notched bottom length and 60 inch top length.

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Transfer Flow 40 Gallon Under Tonneau Cover Auxiliary Tank in truck bed close up

In Bed Auxiliary Fuel Tank System

Transfer Flow's steel in bed auxiliary tanks included a highly advanced diesel fuel auxiliary system that will transfer fuel with an app from your phone.

Both sizes will fit under a standard tonneau cover.

Select the 40 or 50 gallon size for short bed trucks.

  • 40 Gallon - 48"L x 19"W x 19.38"H.
  • 50 Gallon* - 60.75"L x 19"W x 18.25"H.

*The fill neck adds 2.5 inches of height to the top of the tank and is included in the listed height.

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ATI L-Shaped Auxiliary Tank AUX80L

Auxiliary Diesel Fuel Tank

L Shaped auxiliary fuel tanks offer flexibility and additional fuel capacity. These tanks can fit under a bed rail toolbox.

You can also transfer diesel fuel to your truck fuel tank with the fuel transfer kit.

  • 80 Gallon: 48.5"L x 28"W x 26"H.
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ATI Wedge Auxiliary Fuel Tank AUX60W

Aluminum Auxiliary Fuel Tank

Drivers with a 5th wheel prefer wedge shaped auxiliary tanks because of the higher fuel capacity and the sloped design which provides better viewing the truck bed.

  • 60 Gallon: 56"L x 20"W x 18"H
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Auxiliary Fuel Tank Resources

See our guide to the best Auxiliary Fuel Systems.

Unsure of the Best Tank Size? See our Auxiliary Tank Size List by Size & Brand: