Best Aux Fuel Tanks For Trucks: 10 Options Compared

#1 · Best Overall

1. RDS 71083 Auxiliary/Transfer Tank

• Capacity: 45 gallons
• Material: Aluminum

Best for: 45-gallon welded aluminum tank.

Why it ranks #1: The 45-gallon aluminum tank has fully welded seams and is described for auxiliary fueling, with diesel gravity feed and gasoline top-siphon use.

Fully welded seams distinguish the RDS 71083, a 45-gallon aluminum auxiliary/transfer tank that also avoids rusting according to its listing. RDS describes diesel as gravity-feeding from the tank bottom and permits gasoline auxiliary fueling only when siphoned from the top with an electric fuel pump.

The 45-gallon aluminum body pairs fully welded seams with a stated no-rusting material benefit, making the construction relevant to long-term truck-bed use. RDS also describes two different auxiliary-fueling workflows: diesel can gravity-feed from the bottom, while gasoline must be siphoned from the top with an electric fuel pump. Those methods matter when planning connections and choosing a tank for the fuel you intend to carry.

Skip it if you need an integrated toolbox and 90-gallon capacity; the RDS MFG INC 72775 combines both features.

The RDS 71083 fits truck owners seeking a 45-gallon aluminum tank for auxiliary fueling or transfer. Its fuel-specific transfer methods are important setup boundaries, especially for gasoline, which requires a top-siphon electric pump.

Listed on Amazon as: RDS MFG INC 71083 Rectangular Auxiliary/Transfer Fuel Tank – 45 Gallon Capacity

#2 · Highest Capacity

2. RDS 70326 Rectangular Tank

• Capacity: 69 gallons
• Material: Aluminum
• Compatible with Vehicle Type: Multiple vehicle types

Best for: High-capacity auxiliary fuel hauler.

Why it ranks #2: Its 69-gallon aluminum capacity is the largest among the RDS auxiliary-fueling options, and the listing describes gasoline top-siphon and diesel gravity-feed use.

A 69-gallon capacity makes the RDS 70326 the largest specified rectangular option in this lineup, offering substantial onboard reserve for compatible truck setups. Its aluminum body measures 57 by 18 by 16 inches. The listing also describes auxiliary fueling, with different transfer methods noted for diesel and gasoline.

The rectangular aluminum tank’s 69-gallon capacity can reduce how often a work truck needs fuel replenishment, while its 57-by-18-by-16-inch dimensions help assess bed-space demands. RDS describes diesel as gravity-feeding from the tank bottom, whereas gasoline auxiliary fueling requires siphoning from the top with an electric fuel pump. Those different workflows matter when planning a connection; gasoline use is not presented as a simple gravity-feed setup.

Skip it if you want a 20-gallon tank with a storage box above it; the RDS MFG INC 74551 combines those features.

This suits truck owners prioritizing a large auxiliary reserve and able to plan the appropriate fuel-transfer method. Its 69-gallon footprint calls for careful bed-space planning, and gasoline use requires the specified electric-pump arrangement.

Listed on Amazon as: RDS MFG INC Rectangular Auxiliary Fuel Tank – 69 Gallon

#3 · Built-In Toolbox

3. RDS 72775 Tank Toolbox

• Capacity: 90 gallons
• Material: Aluminum
• Compatible with Vehicle Type: Truck

Best for: Fuel storage with integrated toolbox.

Why it ranks #3: This 90-gallon aluminum tank combines auxiliary fuel storage with a built-in toolbox and fully welded seams; the listing says it is not for gasoline.

A built-in toolbox sets this 90-gallon RDS aluminum tank apart, combining auxiliary fuel storage with a place for truck-bed gear. Its 55-by-20-by-19-inch dimensions provide a concrete footprint for planning the bed layout. The product description specifies aluminum diamond-tread construction and says it is not for gasoline use.

The 90-gallon tank and integrated toolbox combine fuel storage and gear storage in one truck-bed unit, which can simplify a setup that would otherwise need separate equipment. RDS specifies fully welded seams, a reinforced lid, and 0.058-gauge aluminum for the toolbox; its description also identifies aluminum diamond tread plate construction. At 55 by 20 by 19 inches, it requires a suitable bed footprint, and the stated fuel limitation rules out gasoline.

Skip it if you need gasoline auxiliary fueling; the RDS MFG INC 71083 allows it when siphoned from the tank top with an electric pump.

This fits truck owners who want a large auxiliary tank and built-in toolbox in one bed-mounted unit. Check that its 55-by-20-by-19-inch footprint works, and note that its stated use excludes gasoline.

Listed on Amazon as: RDS MFG INC 72775 Fuel Tank

#4

4. RDS 71804 Auxiliary Tank

• Capacity: 37 gallons
• Material: Aluminum
• Compatible with Vehicle Type: Car

Best for: 37-gallon auxiliary fueling option.

Why it ranks #4: The 37-gallon aluminum tank is described for auxiliary fueling, including diesel gravity feed and gasoline siphoning from the top with an electric pump.

The RDS 71804 combines a 37-gallon capacity with two stated auxiliary-fueling approaches: diesel can gravity-feed from the tank bottom, while gasoline requires a top siphon and electric pump. Its aluminum body measures 50 by 20 by 9 inches, helping truck owners assess the listed footprint.

The 37-gallon aluminum tank measures 50 by 20 by 9 inches, giving buyers useful dimensions for planning a truck-bed installation. RDS describes a bottom gravity-feed method for diesel, which avoids the gasoline-specific pump workflow. For gasoline auxiliary fueling, the listing requires siphoning from the tank top with an electric fuel pump. That distinction affects setup planning, so the intended fuel should determine which connection arrangement is relevant.

Skip it if you want a 45-gallon tank with fully welded seams; the RDS MFG INC 71083 lists both features.

This RDS suits buyers seeking a 37-gallon aluminum tank and a documented auxiliary-fueling method for their chosen fuel. Its dimensions help with bed planning, while gasoline use requires the specified electric-pump arrangement.

Listed on Amazon as: RDS MFG INC Auxiliary Fuel Tank 37Gal – 71804

#5

5. Dee Zee 91753X Aux Tank

• Capacity: 110 gallons
• Compatible with Vehicle Type: Truck

Best for: 110-gallon truck auxiliary capacity.

Why it ranks #5: The listing specifies a 110-gallon capacity and truck compatibility, making it a high-capacity option, though detailed material and fueling features are not supplied.

The 110-gallon capacity is the defining feature of the DEE ZEE 91753X, offering a substantial auxiliary reserve for truck use. Its listed vehicle compatibility is truck, making the intended application clear. The supplied specifications focus on capacity and compatibility, so buyers should treat those as the main documented decision points.

With 110 gallons listed, this tank is aimed at buyers who prioritize carrying a large auxiliary fuel reserve rather than a modest supplemental supply. The product information identifies truck compatibility, connecting that capacity to the stated vehicle category. The supplied facts do not provide a tank material, dimensions, transfer method, or mounting details; therefore, bed-space planning and installation decisions require information beyond the specifications provided here.

Skip it if you need a documented bed footprint before choosing; the RDS MFG INC 71804 lists dimensions of 50 by 20 by 9 inches.

The 91753X suits truck owners whose priority is a 110-gallon auxiliary reserve. Because the supplied information does not give dimensions or installation details, make sure you can establish bed-space and mounting requirements before choosing it.

Listed on Amazon as: DEE ZEE 91753X Aux Tank, 110 Gallon

#6

6. RDS 74551 Auxiliary Tank

• Capacity: 20 gallons
• Material: Aluminum
• Compatible with Vehicle Type: Truck

Best for: Compact diesel transfer with storage.

Why it ranks #6: This 20-gallon aluminum tank has fully welded seams and heavy-duty mounting brackets; its description targets diesel and other nonflammable liquids.

A storage box on top gives the 20-gallon RDS 74551 a useful dual role: it transfers diesel or other nonflammable liquids while adding bed storage. The aluminum tank has fully welded seams and heavy-duty mounting brackets. RDS also says each tank is pressure-tested and submerged to check for leaks.

The 20-gallon capacity suits buyers who want a smaller transfer supply, while the 50-by-21-by-7-inch dimensions help map its space in a pickup bed. The aluminum construction and fully welded seams support its stated transfer-tank role, and heavy-duty mounting brackets provide a way to secure it. RDS describes the tank as intended for diesel and other nonflammable liquids; its box-on-top configuration adds storage without requiring a separate toolbox for that function.

Skip it if you need a larger auxiliary reserve; the RDS MFG INC 71804 holds 37 gallons and lists auxiliary-fueling methods.

Choose the 74551 for pickup owners who want a compact diesel-transfer tank with storage above it. Its 20-gallon capacity suits smaller supply needs, while the listed dimensions should guide bed-layout planning.

Listed on Amazon as: Rds Aluminum 74551 20 Gal Rectangular Auxiliary Fuel Tank44

#7

7. Better Built 29211584 Tank

• Capacity: 36 gallons
• Material: Alloy Steel

Best for: Baffled steel tank for work trucks.

Why it ranks #7: The 36-gallon steel transfer tank includes a mounting kit, lockable cap, baffles, and an overfill restriction, but the listing does not establish auxiliary connection details.

An overfill restriction that automatically shuts off at the pump is the key convenience of this 36-gallon Better Built tank, helping prevent spills during filling. Its built-in baffles address movement in transit, while flush-mounted two-inch inlet and outlet bungs support fast flow. A lockable cap adds a security measure.

The 36-gallon steel tank combines a pump shutoff feature with built-in baffles: the restriction helps stop overfilling at the pump, while the baffles strengthen the tank and prevent contents from shifting during transport. Two-inch flush-mounted inlet and outlet bungs support fast flow, and the vented lockable cap adds a way to secure the opening. A mounting kit with rubber bushings is included, supporting installation while cushioning the mounting points.

Skip it if you need a larger listed reserve; the RDS MFG INC 70326 holds 69 gallons rather than 36.

Pick the Better Built for work-truck use where controlled filling, flow openings, and a lockable cap matter. Its 36-gallon capacity is a practical boundary for buyers whose trips or work cycles call for a larger reserve.

Listed on Amazon as: Better Built Steel Transfer Fuel Tank – 36-Gallon, Rectangular, Black, Model Number 29211584

#8

8. Dee Zee DZ92556NSB Tank

• Capacity: 128 liters
• Material: Alloy Steel

Best for: Steel tank for bed-mounted transfer.

Why it ranks #8: This 42-gallon steel transfer tank includes five stability baffles and mounting tabs, but its description is for transporting nonflammable liquids rather than auxiliary fueling.

Five stability baffles distinguish this 42-gallon Dee Zee steel transfer tank, helping steady its contents during transport. Its radius-curve construction also addresses weld pressure points, while mounting tabs provide a place to secure the tank in a truck bed. This is a transfer-tank choice, not a documented auxiliary-fueling system.

The 14-gauge alloy-steel body and five stability baffles pair structural construction with measures intended to limit shifting while the tank is carried. A radius curve reduces pressure at weld points, and the mounting tabs give installers a defined way to secure the tank in the bed. Its 59.5-by-19-inch dimensions and 42-gallon capacity help buyers assess bed space and hauling needs; the supplied details identify it for transporting nonflammable liquids.

Skip it if you need a documented auxiliary connection to the truck’s fuel tank; the RDS MFG INC 71083 lists that fueling function.

Choose this Dee Zee for truck-bed transfer of nonflammable liquids when steel construction, baffles, and mounting tabs suit your setup. Its listed role is liquid transfer, so buyers seeking an auxiliary-fueling connection should look elsewhere.

Listed on Amazon as: Dee Zee DZ92556NSB Transfer Tank

#9

9. Landrol 58-Gallon Tank

• Capacity: 58 gallons
• Material: Aluminum
• Compatible with Vehicle Type: Transportation Truck

Best for: Removable aluminum diesel storage.

Why it ranks #9: The 58-gallon aluminum tank includes a sending unit and fuel gauge connection, but its listing explicitly says it is not DOT certified.

Two straps make this 58-gallon Landrol tank removable from the vehicle, a useful distinction for owners who need to take the tank off the truck. Fully welded mounting brackets support installation, while the listed sending unit connects to a fuel gauge to help monitor remaining capacity. The listing says it is not DOT-certified.

The 59-by-13-by-17-inch aluminum tank holds 58 gallons, pairing a substantial stated capacity with a relatively narrow listed width for bed-layout planning. A sending unit connects to the fuel gauge, giving the driver a way to check remaining contents. Fully welded mounting brackets support installation, and two straps allow quicker removal from the vehicle. The product is described for transporting and storing nonflammable liquids; its listing explicitly notes that it has not been DOT-certified.

Skip it if you require a DOT-certified tank; this listing explicitly says the Landrol tank has not been certified.

Consider this Landrol for buyers who value a gauge-linked sender and the option to remove a truck-mounted tank. Its stated capacity and dimensions need to suit the bed, and its non-DOT certification is a decisive boundary.

Listed on Amazon as: 58 Gallon Aluminum Fuel Cell Tank Rectangular Transfer Fuel Tank Auxiliary Diesel Storage for Transportation Truck

#10

10. ATI AUX46R Gas Tank

• Capacity: 46 gallons
• Material: Aluminum
• Compatible with Vehicle Type: Motorcycle, Powersports Vehicles

Best for: 46-gallon powersports auxiliary tank.

Why it ranks #10: Although it lists a 46-gallon capacity, its stated vehicle compatibility is motorcycle and powersports rather than truck, making it the weakest fit for this search.

A 46-gallon capacity is the defining specification of the Aluminum Tank Industries AUX46R, with a listed footprint of 62 by 20 by 14 inches. Its vehicle compatibility is identified as motorcycles and powersports vehicles, not trucks. That compatibility detail makes this a specialized option to assess carefully for a truck-focused auxiliary-tank roundup.

The AUX46R offers 46 gallons in an aluminum tank measuring 62 by 20 by 14 inches, so those dimensions and capacity are the main supplied planning details. The listing identifies motorcycles and powersports vehicles as compatible vehicle types, which is a significant distinction for truck owners: it does not provide truck compatibility information. No transfer method or installation hardware is specified in the supplied facts, so those details cannot be assumed from the capacity alone.

Skip it if you need an explicitly truck-compatible tank; the DEE ZEE 91753X lists truck compatibility and a 110-gallon capacity.

This is relevant to a buyer researching a 46-gallon auxiliary tank for a motorcycle or powersports vehicle. For truck use, the supplied compatibility information is the key boundary, so verify that this application is appropriate before proceeding.

Listed on Amazon as: AUX46R Auxiliary Gas Tank – 46 Gallon Capacity