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Under Tonneau Cover Fuel Tanks

Browse our selection of auxiliary tanks, transfer tanks, and tank toolbox combos designed to fit under a tonneau cover. Auxiliary tanks transfer diesel fuel directly to your truck's diesel fuel tank.  Choose a transfer tank if you want a portable fuel tank with a fuel pump to dispense fuel.  Transfer tanks can hold multiple fuel types including both gas and diesel.

Scroll down for detailed dimensions for each tank.  

Not sure which tank is best for your truck bed?

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Transfer Flow Low Profile Under Tonneau Cover Transfer Tank with fuel pump
$1,761.05 - $1,761.05
$1,761.05
$1,761.05 - $1,761.05
$1,761.05

Transfer Flow Low Profile Under Tonneau Cover Transfer Tank

If you need a low profile fuel transfer tank that fits under most standard sized tonneau covers, Transfer Flow offers a 40 gallon tank with a 12V G...

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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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$1,223.00 - $1,494.00
$1,223.00
$1,249.00 - $1,494.00
$1,249.00 - $1,494.00
$1,249.00

ATTA DOT Approved Under Tonneau Cover Transfer Tank

ATTA DOT Approved Low Profile Under Tonneau Cover Transfer Tank is a DOT legal tank. The tank design includes a lower height fuel bung that enable...

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ATI Rectangle Refueling Transfer Tank 51 gallon Sale Sale
$655.88 - $857.35
$655.88 - $857.35
$655.88
$557.50 - $1,113.75
$557.50 - $1,113.75
$557.50

ATI Rectangle DOT Approved Aluminum Transfer Tank

Aluminum Tank Industries rectangle DOT approved aluminum fuel transfer tanks are legal in all 50 states for gasoline, kerosene, methanol, diesel, a...

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ATI Rectangle Refueling Transfer Tank 38 gallon
Sale Sale
$644.12 - $711.76
$644.12 - $711.76
$644.12
$547.50 - $605.00
$547.50 - $605.00
$547.50

ATI Rectangular DOT Approved Aluminum Transfer Tank

Aluminum Tank Industries rectangle Refueling aluminum Transfer Tanks are legal in all 50 states for gasoline, kerosene, methanol, diesel, and aviat...

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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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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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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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Fuelbox FTC44T under tonneau fuel tank toolbox combo
$1,900.00 - $2,485.00
$1,900.00 - $2,485.00
$1,900.00 - $2,485.00
$1,900.00

The Fuelbox Under Tonneau Fuel Tank Toolbox Combo

The Fuelbox Under Tonneau is a low profile fuel tank toolbox combo.  This fuel tank toolbox combo is designed to work with most tonneau covers. The...

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ATTA Auxiliary Tank Toolbox Combo short bed 34 gallon
$1,463.00 - $2,182.00
$1,463.00 - $2,182.00
$1,463.00 - $2,182.00
$1,463.00

ATTA Diesel Auxiliary Tank & Toolbox Combo (Short Bed)

The aluminum ATTA diesel under tonneau auxiliary tank and toolbox short bed combo is designed for short bed trucks. The tank is constructed with ....

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Transfer Flow Low Profile Under Tonneau Cover Transfer Tank with fuel pump on the side

Under Tonneau Cover Fuel Tank with Pump

This Transfer Flow transfer tank offers a side holstered GPI fuel pump with a 17.5 inch tank height designed to fit under a standard tonneau cover.

The fuel tank holds your choice of gas, diesel, methanol, ethanol or kerosene.

  • 40 Gallon: 40 inches Long by 23 inches Wide by 17.5 inches High.
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Fuelbox FTC44T under tonneau fuel tank toolbox combo

Under Tonneau Fuel Tank Toolbox Combo

The Fuelbox under tonneau cover fuel tank toolbox combo is designed to securely fit under most standard tonneau covers.

*If you have a short bed pickup, choose the 40 gallon size.

  • 40 Gallon: 62 inches Long by 23 inches Wide by 17.5 inches High.
  • 45 Gallon: 62 inches Long by 20 inches Wide by 17.5 inches High.
  • 55 Gallon: 53 inches Long by 30 inches Wide x 17.5 inches High.
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Transfer Flow 50 Gallon Under Tonneau Cover Auxiliary Tank in truck bed from above

Under Bed Auxiliary Fuel Tanks for Pickup Trucks

Transfer Flow's auxiliary diesel fuel tank will transfer diesel fuel directly into your diesel truck's fuel tank. Choose from two sizes which both fit under a standard tonneau cover.

  • 40 Gallon: 48 inches long x 19 inches wide x 19.38 inches high.
  • 50 Gallon: 60.75 inches long x 18.5 inches wide x 18.25 inches high.

*2.5 inch fill neck is included in the dimensions.

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Transfer Tank Under Tonneau Cover

ATTA offers a unique design that enables a top mounted fuel pump to remain under a tonneau cover.

Choose the 38 gallon size for a standard hard cover or choose the 41 gallon size for a Roll Top canister style cover.

  • 38 Gallon: 60"L x 12"W x 15"H (standard tonneau cover).
  • 41 Gallon: 60"L x 18"W x 14"H (cannister style tonneau cover).

*Fuel pump is not included with the tank, but is available with the ATTA tank as an optional add-on product.

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ATTA Diesel Auxiliary Roll-Top Bedcover Tank 45 gallon

Under Tonneau Roll Top Auxiliary Tank

This diesel auxiliary fuel tank is designed with a 7 inch height lower L shape to fit under a roll top canister tonneau cover.

This tank offers sizes for both long bed and short bed trucks.

  • 45 Gallon: 60 inches long x 18 inches wide x 14 inches high.
  • 72 Gallon: 60 inches long x 25 inches wide x 14 inches high.
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ATI AUX30R auxiliary fuel tank

Tonneau Cover Auxiliary Tank

ATI offers multiple diesel auxiliary aluminum fuel tanks that fit underneath a tonneau cover.

*ATI tanks 50 gallons and less ship by UPS.

  • 30 Gallon*: 48.5 inches long x 19 inches wide x 9 inches high.
  • 42 Gallon: 18.5 inches long x 11 inches wide x 19 inches high.
  • 43 Gallon*: 58 inches long x 12 inches wide x 16.5 inches high.
  • 46 Gallon: 57 inches long x 12 inches wide x 16.5 inches high.

*30 gallon size has a 3.5 inch fill cap / other sizes have 2.5 inch. 43 gallon size has a 51 inch notched bottom length.

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Tonneau Cover Height Ranges

Fitting a fuel tank underneath your tonneau cover requires matching up the correct measurements of your tonneau cover and the fuel tank.

Most tonneau covers have the following height ranges:

  • 17 inches of height to 21 inches of height. 

Because of the wide range of heights, it’s really important to measure the actual height underneath your tonneau cover before you make a decision on a fuel tank.

*If you have a Roll Top canister style tonneau cover, this creates a lower initial space in the front of your bed. Look for fuel tanks that are designed for a Roll Top cover like ATTA.

Additional Tank Options: