It is important to have the best 40 gallon auxiliary fuel tank. Let’s take you step by step, type by type, and find the best 40 gallon auxiliary fuel tank for you.

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Our Top Picks:

Best Overall: Buy: Rds Mfg Inc Stock Fuel Tank READ REVIEW

Best For Lifetime Warranty: Buy: Titan Fuel Tanks 40 Gallon Auxiliary Fuel Tank READ REVIEW

Best For Pickup: Buy: Mts 40 Gallon Auxiliary Fuel Tank READ REVIEW

Best With Part Number: Buy: Rds Mfg Inc 40 Gallon Auxiliary Fuel Tank READ REVIEW

Best For Gas: Buy: Dee Zee 40 Gallon Auxiliary Fuel Tank READ REVIEW

Best Overall: Rds Mfg Inc Stock Fuel Tank

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The Rds Mfg Inc Stock Fuel Tank should be able to handle its purpose and duties with ease. The rds mfg inc stock fuel tank is dual, is easier and it fits well. Make sure this fits by entering your model number. This tank offers extra fuel capacity for a truck bed, generator, or other specialty application using diesel fuel.

Most importantly, the rds mfg inc stock fuel tank is very happy and it is easy to use.

Almost all customers opine that the tank can only get fifty gallons in it, not 60 as advertised. Moreover, they strongly agree that the tank is designed for exterior areas. And, a few also found that this tank is about 20 inches from front to back. You would have to measure it to determine fitment for your truck. In short, many customers have used the tank for more than a few months without any complaints, and it shows no sign of giving up.

• This will be about 5/8” for the supply hose to run through.
• It is about 1 hour to transfer approx.
• This includes a fuel gauge and fits under a bed cover.
• This is gravity fed in various sizes.

Best For Lifetime Warranty: Titan Fuel Tanks 40 Gallon Auxiliary Fuel Tank

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The Titan Fuel Tanks 40 Gallon Auxiliary Fuel Tank's material feels more premium than its price would suggest. The titan fuel tanks 40 gallon auxiliary fuel tank comes with one touch of a button, The remarkable titan electronic controller pumps fuel from the travel trekker to the vehicle's primary fuel tank until it is automatically stopped by the controller or the button is touched again. The Manufacturer says: The titan travel trekker 40 is made of our famous military - grade, cross-linked polymer. This innovative 40 gallon product works great with most any full - sized diesel truck.

The tank is simple and never requires cutting into the vehicle's wiring harness, which could affect the manufacturer's warranty. And, the tank includes half ton pickups with utility beds, those equipped with a rambox(r), and those equipped with a factory 5th wheel package. Above all, the titan fuel tanks 40 gallonauxiliary fueltank will fit many mid-sized vehicles, is baffled to minimize fuel sloshing and will even fit under most tonneau covers.

Most buyers found that the tank is designed for diesel fuel only not gasoline. Moreover, a few say that the tank is possible, however that the system is said to not fit due. Further, they also found that this tank will fit all trucks, including the 3500 rambox which has a narrower. Consequently, customers were eager to recommend it to friends and families.

• This is made for heavy duty and it fits perfectly.
• Manufacturer says: we routinely test our products using state.
• One of the newcomers and featured product.

Best For Pickup: Mts 40 Gallon Auxiliary Fuel Tank

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Not everyone likes to purchase a tank for their regular usage, but the MTS 40 gallon auxiliaryfuel tank would be an anomoly. The MTS 40gallon auxiliary fuel tank fits right up and it is perfect for a good deal. Make sure this fits by entering your model number. This tank does not include a sending unit, an ems valve or an ems valve gasket.

The tank is great for fast shipping and it is blue. Most importantly, the MTS 40 gallonauxiliary fueltank comes with quick shipping and it is great for direct replacement.

Almost all buyers agree that the tank will take some modifications though. And, a few also found that the tank is a diesel....yours must fit after the axle. And, a few strongly agree that the tank is designed to go after the rear axle. Without any doubt, this product passed the test and had very satisfied buyers eager to share their experience.

• F550 super duty series "diesel only" 40 gallon rear truck tank.
• This will not work with gas as there is no fuel pump mount.
• One of the newcomers and featured product.

Best With Part Number: Rds Mfg Inc 40 Gallon Auxiliary Fuel Tank

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The Rds Mfg Inc 40 Gallon Auxiliary Fuel Tank's material feels more premium than its price would suggest. And, this is allowed, if siphoned from the top of the tank by using an electric fuel pump. An optional diesel install kit contains the necessary items to economically and easily connect your RDS tank to your own fuel tank. Finally, the rds mfg inc 40gallon auxiliaryfuel tank is compatible with part number and it is great for high quality.

Almost all customers quickly discovered that the tank was a nice tank, but the fuel cap leaks. In addition, a few also found that this tank is variously described as 40 gallons, 45 gallons, and 48 gallon.s. With no doubts, this tank passed the test and had very satisfied buyers eager to share their experience.

• Package dimensions :22.86 cm l x50.8 cm w x152.4 cm h.
• Auxiliary tanks connect to your vehicle’s fuel tank.
• Good investment for the long term.

Best For Gas: Dee Zee 40 Gallon Auxiliary Fuel Tank

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Best part: Dee Zee 40 Gallon Auxiliary Fuel Tank costs comparatively low and it is available to ship in 24 hours. The dee zee 40 gallon auxiliary fuel tank has a drain plug and it fits well. Dee zee’s classic styles are intertwined with the newest modern looks to explicitly satisfy your needs. Moreover, the tank has been a staple brand in the truck accessory market since 1977.

The tank is compatible with center mounted transfer pumps. In addition, it is made with a good product, it is straight - forward and has a good design. Most importantly, the dee zee 40 gallon auxiliary fuel tank fits in front of the truck bed.

Almost all buyers opine that the tank has an extra hole on top. Further, a few say that the tank does have baffles, and on the f350 the filler neck is above the rails. Moreover, a few strongly agree that the tank looks great when installed, but only gave it four stars because the fuel transfer rate is very slow. In conclusion, the tone of buyers is very positive and we believe that the tank suits the purpose.

• This is constructed of heavy gauge brite-tread aluminum.
• The Manufacturer says: our extensive product lines are built with you in mind.
• This is great for gas cap and it allows for a great fit.
• Connect to oem fuel line to transfer diesel fuel.