Best Auxiliary Tanks For Diesels: Compare 10 Options

#1 · Best Overall

1. RDS 69-Gallon Auxiliary Tank

• Capacity: 69 gallons
• Material: Aluminum
• Weight: 16 oz

Best for: High-capacity auxiliary fueling.

Why it ranks #1: Its listing specifically describes diesel gravity feed from the tank to the vehicle, and its 69-gallon aluminum capacity is the largest listed RDS auxiliary option.

A 69-gallon capacity gives this RDS tank substantial onboard diesel storage, while its 57-by-18-by-16-inch rectangular footprint makes the required bed space clear before installation. RDS says diesel can gravity-feed from the tank’s bottom when connected to the vehicle’s fuel tank, supporting auxiliary fueling without a transfer-pump feature being listed.

The 69-gallon capacity suits buyers prioritizing extended onboard fuel supply, and the aluminum construction keeps the tank material distinct from steel options. Its 57-by-18-by-16-inch dimensions give truck owners concrete measurements for planning placement and available bed space. RDS describes diesel gravity-feeding from the tank bottom when connected to the vehicle fuel tank, so it serves an auxiliary-fueling workflow; the listing does not specify a pump or detailed installation hardware.

Skip it if you need a compact 37-gallon footprint; the RDS 71804 measures 50 by 20 by 9 inches.

Truck owners seeking a large auxiliary diesel reserve and a gravity-feed connection described by RDS are the natural audience. Check the 57-inch length and available bed space carefully; the listing does not specify a transfer pump.

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

#2 · Best Toolbox Combo

2. RDS 60-Gallon Toolbox Combo

• Capacity: 60 gallons
• Material: Alloy Steel, Aluminum, Stainless Steel
• Weight: 16 oz

Best for: Toolbox-and-fuel storage combo.

Why it ranks #2: This 60-gallon RDS combo is described as an auxiliary and transfer tank with a toolbox, and RDS says its tanks can connect to the vehicle fuel tank.

A 60-gallon capacity combined with a toolbox gives this RDS model a dual-purpose truck-bed format for fuel storage and gear. Its listed dimensions of 55 by 20 by 19.5 inches help with placement planning, and RDS describes diesel gravity feed from the tank bottom when connected to the vehicle’s fuel tank.

The 60-gallon capacity provides a substantial reserve, while the toolbox combination makes the unit relevant to truck owners seeking fuel storage alongside tool storage. Its 55-by-20-by-19.5-inch dimensions offer a concrete basis for checking bed layout. RDS says diesel can gravity-feed from the tank bottom when connected to the vehicle fuel tank, supporting auxiliary fueling. The listing names alloy steel, aluminum, and stainless steel among its materials, but does not specify a transfer pump.

Skip it if you need powered transfer specified in the listing; the VEVOR 116-gallon tank includes a 12V DC pump.

Truck owners wanting a 60-gallon fuel reserve alongside toolbox storage may find this RDS combo relevant. Check the 19.5-inch height and bed layout, and note that the listing does not specify a transfer pump.

Listed on Amazon as: RDS MFG INC – 72548 Fuel Transfer Tank/Auxiliary Fuel Tank/Toolbox Combo – 60 Gallon

#3 · Best Mid-Size

3. RDS 45-Gallon Auxiliary Tank

• Capacity: 45 gallons
• Material: Aluminum
• Weight: 42 lb

Best for: Rust-resistant aluminum reserve.

Why it ranks #3: The 45-gallon aluminum tank is explicitly described as auxiliary/transfer, with RDS diesel gravity-feed capability and fully welded seams.

Fully welded seams and aluminum construction distinguish this 45-gallon RDS tank, combining a defined capacity with a material the listing describes as non-rusting. RDS says diesel can gravity-feed from the tank bottom when connected to the vehicle fuel tank, giving diesel truck owners an auxiliary-fueling path without a pump listed as included.

The 45-gallon capacity provides a substantial reserve while taking less fuel volume than larger listed tanks. Fully welded seams are specified for durability, and aluminum construction is identified as resistant to rusting, making the material relevant for a tank carried in a truck. RDS describes bottom-fed diesel gravity feed after connection to the vehicle tank. The listing does not provide dimensions or identify a transfer pump, so buyers should assess installation and space separately.

Skip it if you need published dimensions before deciding placement; the RDS 71804 lists a 50-by-20-by-9-inch footprint.

Diesel truck owners wanting a 45-gallon aluminum auxiliary tank with welded seams should consider this RDS model. Its missing dimensions make advance bed-space planning harder, and no transfer pump is specified in the supplied listing.

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

#4

4. RDS 37-Gallon Auxiliary Tank

• Capacity: 37 gallons
• Material: Aluminum
• Weight: 77 lb

Best for: Low-profile auxiliary tank.

Why it ranks #4: RDS describes its auxiliary tanks as connecting to the vehicle’s fuel tank and diesel as gravity-feeding; this model offers a smaller 37-gallon aluminum capacity.

At 50 by 20 by 9 inches, this 37-gallon RDS aluminum tank offers a relatively low listed height for buyers planning truck-bed placement. RDS says diesel can gravity-feed from the tank bottom when connected to the vehicle’s fuel tank, giving the tank an auxiliary-fueling role without a pump specified in the listing.

The 37-gallon capacity offers a defined reserve, while the 9-inch listed height helps buyers assess clearance in a truck-bed layout. Aluminum construction keeps the tank material clear, and RDS describes diesel gravity-feeding from the bottom when the tank connects to the vehicle fuel tank. The 50-by-20-inch footprint still needs to be planned against available space. No transfer pump is specified, so this listing supports an auxiliary gravity-feed workflow rather than a stated powered-dispensing setup.

Skip it if you need more than 37 gallons onboard; the RDS 70326 holds 69 gallons, though it measures 57 inches long.

Truck owners seeking a low-profile aluminum auxiliary tank with RDS-described gravity feed should consider this 37-gallon model. Its capacity is the key boundary, and the 50-by-20-inch footprint still needs to fit the intended space.

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

#5 · Best Baffled Steel

5. Dee Zee 42-Gallon Transfer Tank

• Capacity: 128 liters
• Material: Alloy Steel
• Weight: 70 lb

Best for: Baffled steel truck-bed tank.

Why it ranks #5: Its 42-gallon steel tank has five stability baffles, mounting tabs, and a lockable cap, though the listing presents it as a transfer tank rather than a vehicle-feed auxiliary.

Five stability baffles and a radius-curve design distinguish this 42-gallon Dee Zee steel transfer tank, addressing movement during transport and weld pressure points. Mounting tabs secure it to the truck bed, while the black NRT rust-inhibitor powder-coat finish is specified as protection for the steel tank.

The 42-gallon capacity gives truck owners a defined reserve, and the 59.5-inch width by 19-inch height helps with bed-space planning. Dee Zee specifies 14-gauge steel and a radius curve that eliminates weld pressure points; five stability baffles address shifting during transport. Mounting tabs secure the tank to the bed. A drain plug supports draining, and the listed NRT rust-inhibitor powder-coat finish provides a protective surface for the steel.

Skip it if you need a pump included for powered dispensing; the BLACKHORSE-RACING LZ69801 lists a 10-GPM pump and hose.

This Dee Zee suits truck owners who want a baffled steel tank secured by bed mounting tabs, with a drain plug for maintenance. Measure the 59.5-inch width against available bed space before choosing it.

Listed on Amazon as: Dee Zee DZ92556NSB Transfer Tank

#6

6. Better Built 36-Gallon Steel Tank

• Capacity: 36 gallons
• Material: Alloy Steel
• Weight: 40 lb

Best for: Baffled steel transport tank.

Why it ranks #6: The 36-gallon steel transfer tank includes a mounting kit, baffles, and a lockable cap, but the listing does not specify a diesel auxiliary-feed connection.

Built-in baffles help keep contents from shifting during transport, giving this 36-gallon Better Built steel tank a practical advantage for moving fuel in a working truck. Its overfill restriction automatically shuts off at the pump to help prevent spills, while a lockable cap adds a measure of access security.

The 36-gallon capacity provides a defined fuel reserve, and alloy-steel construction suits buyers who prefer a steel tank. During transport, the built-in baffles add strength and help prevent contents from shifting; at filling time, the overfill restriction automatically shuts off at the pump to prevent spilling. Flush-mounted two-inch inlet and outlet bungs allow fast flow, while the included mounting kit with rubber bushings supports installation. A lockable cap helps secure access.

Skip it if you want a larger reserve; the VEVOR 116-gallon portable tank lists a 10.6-GPM transfer pump.

Choose this Better Built when a 36-gallon steel tank, baffled transport, and pump-side overfill shutoff match your work routine. Its capacity is the boundary: buyers needing a larger reserve should consider a higher-capacity option.

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

#7 · Best Portable Pump

7. CAMMOO 58-Gallon Portable Tank

• Capacity: 58 gallons
• Material: Aluminum, High Density Polyethylene (HDPE)…
• Weight: 68.8 lb

Best for: Portable high-capacity diesel transfer.

Why it ranks #7: This 58-gallon portable diesel tank includes a 12V pump rated at 13.2 GPM in its title, but it is not described as connecting to a truck fuel tank.

A stated 13.2-GPM rate pairs with a 58-gallon capacity, positioning this CAMMOO as a portable diesel transfer tank for moving a substantial reserve. Its flame-retardant LLDPE and HDPE construction is specified for outdoor exposure, with resistance to UV, rain, snow, wear, and corrosion, and the listing says it meets DOT requirements.

The 58-gallon capacity supports carrying a sizeable diesel supply, while the 13.2-GPM figure in the title identifies its stated transfer rate. CAMMOO describes the LLDPE and HDPE tank as resistant to UV, rain, snow, wear, and corrosion, useful context for outdoor use. A combo lock is specified to protect stored fuel and ease access. The stated operating range with fuel inside is 14°F to 104°F, a boundary to account for in use.

Skip it if you need use with fuel below 14°F or above 104°F; this tank’s listed operating range excludes those conditions.

This CAMMOO suits buyers moving diesel outdoors who value a 58-gallon capacity, stated transfer rate, and lockable access. Keep the 14°F–104°F operating range with fuel inside in view when planning where and when to use it.

Listed on Amazon as: CAMMOO Real 58 Gallon Portable Diesel Fuel Transfer Tank, 13.2 GPM, 12V DC

#8

8. BLACKHORSE-RACING 51-Gallon Combo

• Capacity: 51 gallons
• Material: Aluminum

Best for: Pump-and-toolbox combo buyers.

Why it ranks #8: The 51-gallon aluminum toolbox combo includes a 10 GPM 12V pump, nozzle, and 13.1-foot hose, but its listing does not establish auxiliary fuel-system compatibility.

A 10-GPM 12V DC pump, automatic nozzle, and 13.1-foot hose make this 51-gallon BLACKHORSE-RACING combo ready for powered fuel transfer as listed. Its black aluminum tank combines fuel storage with a toolbox, while a double lock and keys protect the internal pump and supplies.

The 51-gallon capacity provides onboard storage, and the 10-GPM pump gives the listed transfer workflow a specific rate. Its 12V DC power, automatic refueling nozzle, and 13.1-foot hose support dispensing from the tank without a separate nozzle being specified. The combo format pairs the tank with a toolbox, and the double lock protects the internal pump and supplies. The listing explicitly says the package does not contain a filter, which matters when planning the setup.

Skip it if you require a filter in the package; this BLACKHORSE-RACING tank explicitly lists none included.

Truck owners wanting fuel storage, a toolbox, and powered transfer in one combo should consider this 51-gallon model. Its listed package lacks a filter, so buyers whose setup requires one must account for that separately.

Listed on Amazon as: 51 Gallons Combo Aluminum Fuel Transfer Tank, with 10 GPM Fuel Transfer Pump/Gasoline Diesel Transfer Tank & Toolbox/Auxiliary Fuel Tank-Black

#9

9. VEVOR 116-Gallon Portable Tank

• Capacity: 400 gallons
• Material: Polyethylene (PE)
• Weight: 104.1 lb

Best for: Large-volume portable diesel supply.

Why it ranks #9: Its listed configuration provides a 116-gallon polyethylene tank and 10.6 GPM 12V pump, but it is a portable transfer tank, not a stated vehicle-feed auxiliary.

A 116-gallon capacity and a listed 10.6-GPM maximum flow rate make this VEVOR portable diesel tank suited to moving a large supply. Its 12V DC pump, 13.1-foot hose, and lockable polyethylene tank combine powered dispensing with protected storage for mobile fueling workflows.

The listed 116-gallon capacity supports carrying a large diesel reserve, while the 10.6-GPM maximum flow and 12V DC pump provide a specified transfer setup. A 13.1-foot hose and an equally long electric wire give reach between the tank and dispensing point. VEVOR specifies polyethylene construction that resists UV and changing weather, plus a copper lock on the upper lid. At 104.1 pounds listed weight, the tank is a substantial portable unit to account for when handling.

Skip it if you need a lighter listed tank; the CAMMOO 58-gallon portable model weighs 68.8 pounds.

This VEVOR fits users moving large diesel volumes who want a specified pump, hose, and lockable portable tank. Its 104.1-pound listed weight and 116-gallon scale make handling and placement important considerations.

Listed on Amazon as: VEVOR Portable Diesel Tank 116 Gallon Capacity & 10 GPM Portable Fuel Tank

#10

10. Landrol 58-Gallon Aluminum Tank

• Capacity: 58 gallons
• Material: Aluminum

Best for: Removable aluminum truck tank.

Why it ranks #10: This 58-gallon aluminum storage tank lists a sending unit and mounting straps but explicitly says it is not DOT certified and gives no auxiliary-feed method.

A 58-gallon aluminum tank comes with oil pipes, vent covers, and sending units that connect to a fuel gauge, helping users check remaining capacity. Landrol also specifies fully welded mounting brackets and two straps, supporting installation on a truck and quicker removal when the tank needs to come off the vehicle.

At 59 by 13 by 17 inches, the rectangular tank gives truck owners dimensions for planning placement, while its 58-gallon capacity offers substantial storage. The sending units connect to a fuel gauge to facilitate checking remaining capacity; oil pipes and vent covers are also specified. Fully welded mounting brackets support installation onto a truck, and the two straps make removal quicker. Landrol explicitly states that the tank has not been DOT certified, a key transport consideration.

Skip it if you require a DOT-certified tank; the CAMMOO 58-gallon portable diesel tank states that it meets DOT requirements.

Truck owners seeking a 58-gallon aluminum tank with gauge-connected sending units and removable straps may find the setup useful. Its stated lack of DOT certification is a decisive boundary for buyers with certification requirements.

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