Expanding your truck’s fuel range or needing a convenient way to transfer fuel for equipment requires a reliable and safe fuel box. In our comprehensive buying guide, we researched, compared, and evaluated a wide array of auxiliary fuel tanks and transfer tanks designed for truck beds and underbody mounting. Our analysis is based on manufacturer specifications, industry safety standards, and aggregated owner feedback to provide an evidence-based recommendation.
We focused on key factors such as material durability, capacity, fuel compatibility, installation requirements, and overall user experience to help you make an informed decision. Whether you’re a long-haul driver, operate heavy equipment, or simply need extended fuel capacity, our top picks offer strong solutions for various needs and budgets.
| Photo | Product | Score | Buy |
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Dee Zee DZ91757 Auxiliary Fuel Tank Top Pick: Overall Performance 75 Gallon Capacity, L-Shaped, Heavy Gauge Aluminum, Diesel Compatible |
9.1 | 🛒 Check Price |
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RDS Manufacturing 72740 Auxiliary Diesel Fuel Tank Runner-Up: Durable and Reliable 70 Gallon Capacity, L-Shaped, Aluminum, Diesel Only |
8.7 | 🛒 Check Price |
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Weather Guard 355-3-01 Transfer Tank Best for Multi-Fuel Use 50 Gallon Capacity, Rectangular, 14 Gauge Steel, Multi-Fuel |
8.4 | 🛒 Check Price |
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Titan Fuel Tanks 5010026 Underbed Auxiliary Fuel Tank Best Underbed Solution 50 Gallon Capacity, Underbed Mount, High-Density Polyethylene, Diesel Only |
8.1 | 🛒 Check Price |
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GPI 100 Gallon Aluminum Fuel Transfer Tank High Capacity Pick 100 Gallon Capacity, Rectangular, Aluminum, Multi-Fuel |
7.9 | 🛒 Check Price |
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Delta PRO Series 40 Gallon Steel Transfer Tank Value-Oriented Steel Option 40 Gallon Capacity, Rectangular, 14 Gauge Steel, Multi-Fuel |
7.6 | 🛒 Check Price |
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ATT Auxiliary Fuel Tank (Aluminum, 50 Gallon, L-Shaped) Budget-Friendly Aluminum 50 Gallon Capacity, L-Shaped, Aluminum, Diesel Only |
7.3 | 🛒 Check Price |
1. Dee Zee DZ91757 Auxiliary Fuel Tank: Top Pick: Overall Performance
In our evaluation, the Dee Zee DZ91757 stands out for its superior build quality and thoughtful design. The .125 thick Brite-Tread aluminum construction provides excellent corrosion resistance and durability, a critical factor for long-term use in various conditions. Based on owner feedback and the spec sheets, its fully welded seams and pressure testing ensure a high level of reliability and safety against leaks, which is paramount when transporting flammable liquids. The L-shaped profile is a practical advantage, often allowing for additional storage solutions in the truck bed.
A notable limitation of this model is its primary compatibility with diesel fuel, which means gasoline users will need to consider other options. Also, the tank does not include a pump or gravity feed kit, requiring an additional purchase and installation steps. Therefore, users who require a multi-fuel solution or prefer an all-in-one package with a pump already integrated might find this pick less convenient and should explore alternatives.
- Constructed from .125 thick non-rusting Brite-Tread aluminum for longevity.
- Equipped with a radius curve design to minimize sloshing and enhance tank integrity.
- Designed with a fully welded, pressure-evaluated construction for leak prevention and safety compliance.
Pros: Exceptional build quality and solid aluminum construction.; Integrated baffles and a vented cap contribute to safe fuel management.; L-shaped design often allows for toolbox mounting above the shorter end.
Cons: Requires a separate fuel transfer pump or gravity feed kit, not included.; Primarily designed for diesel fuel, limiting versatility for gasoline users.
2. RDS Manufacturing 72740 Auxiliary Diesel Fuel Tank: Runner-Up: Durable and Reliable
The RDS Manufacturing 72740 earned high marks in our comparison for its sturdy construction and dedicated design for diesel fuel transport. We researched its heavy-duty aluminum build, which offers superior corrosion resistance compared to steel options, a key benefit for longevity. The inclusion of a manual sight gauge is a practical feature, based on owner feedback, allowing for quick and easy monitoring of fuel levels without needing to open the tank. Its compliance with DOT standards for diesel transport further reinforces its safety credentials.
However, a significant drawback is its exclusive compatibility with diesel fuel, making it unsuitable for those needing to transfer gasoline. Additionally, while the 3/8 inch NPT fuel line connection is standard, integrating this auxiliary tank into a truck’s fuel system can be complex and may require professional installation to ensure proper function and safety. Therefore, individuals seeking a flexible tank for multiple fuel types or those uncomfortable with intricate fuel system modifications should consider other options that offer broader compatibility or simpler installation.
- Constructed from heavy-duty aluminum for strength and resistance to rust.
- Features a 3/8 inch NPT fuel line connection for easy integration with truck fuel systems.
- Includes a manual sight gauge to monitor fuel levels conveniently.
Pros: Durable aluminum construction provides excellent durability.; Sight gauge is a practical addition for quick fuel level checks.; Designed with safety in mind, meeting DOT standards for diesel fuel transport.
Cons: Specifically for diesel fuel, not suitable for gasoline.; Installation often requires professional assistance for optimal integration.
3. Weather Guard 355-3-01 Transfer Tank: Best for Multi-Fuel Use
The Weather Guard 355-3-01 stands out in our comparison for its exceptional multi-fuel compatibility, accommodating diesel, gasoline, kerosene, and even aviation fuel. This versatility, based on manufacturer specifications, is a significant advantage for users who need to transfer various types of fuel. The 14 gauge steel construction, while heavier than aluminum, provides strong impact resistance and is finished with a durable white powder coat that helps protect against the elements and corrosion.
However, the primary limitation of this transfer tank is its steel construction. While strong, steel is inherently heavier than aluminum, which can reduce payload capacity and impact fuel efficiency for some truck owners. More critically, if the powder coat finish is scratched or damaged, the underlying steel can be susceptible to rust over time, potentially compromising the tank’s integrity. Therefore, users prioritizing lightweight solutions or those operating in harsh, corrosive environments without vigilant maintenance might find aluminum tanks a more suitable, albeit potentially more costly, long-term investment.
- Constructed from heavy-duty 14 gauge steel with a durable white powder coat finish.
- Designed for use with diesel, gasoline, kerosene, and aviation fuel.
- Features a lockable cap and a 2 inch NPT reinforced bungs for secure pump mounting.
Pros: Adaptable compatibility with multiple fuel types, including gasoline.; Solid 14 gauge steel construction offers strong impact resistance.; Powder coat finish enhances durability and corrosion protection.
Cons: Steel construction is heavier than aluminum alternatives.; Prone to rust if the powder coat finish is compromised over time.
4. Titan Fuel Tanks 5010026 Underbed Auxiliary Fuel Tank: Best Underbed Solution
In our evaluation, the Titan Fuel Tanks 5010026 offers a unique advantage by mounting under the truck bed, preserving valuable cargo space. Its construction from high-density, cross-linked polyethylene provides exceptional durability, resisting rust, dents, and punctures more effectively than metal tanks in certain scenarios. Based on owner feedback and the spec sheets, the integrated electronic fuel transfer control unit simplifies fuel management, automatically transferring fuel to the main tank as needed, which is a significant convenience for long-distance driving.
A notable limitation of this system is its installation complexity. Underbed mounting requires more specialized tools and time, and the integration of electronic components into the truck’s fuel system can be challenging for the average DIY installer. This often necessitates professional installation, adding to the overall cost. Therefore, users who require a straightforward, easily removable solution, or those with limited mechanical experience and budget for professional installation, might find traditional truck bed-mounted tanks to be a more practical choice.
- Constructed from extra heavy duty, cross-linked polyethylene for exceptional durability.
- Designed to mount under the truck bed, preserving valuable bed space.
- Includes a proprietary electronic fuel transfer control unit for smooth integration.
Pros: Frees up truck bed space, a major advantage for cargo needs.; Polyethylene construction is rust-proof and highly resistant to impact.; Electronic transfer system offers convenient, automatic fuel management.
Cons: More complex installation due to underbed mounting and electronic components.; Higher initial cost compared to many truck bed-mounted tanks.
5. GPI 100 Gallon Aluminum Fuel Transfer Tank: High Capacity Pick
The GPI 100 Gallon Aluminum Fuel Transfer Tank is a compelling option for those requiring substantial fuel capacity. In our comparison, its 100 gallon volume stands out, making it ideal for operating heavy machinery, extended journeys, or remote work sites. The aluminum construction, protected by a clear powder coat, provides a good balance of durability and lighter weight compared to steel tanks of similar capacity, and based on manufacturer specifications, it offers broad multi-fuel compatibility, which is a key advantage.
However, the significant capacity of this tank comes with a notable drawback: its large footprint. Occupying a considerable portion of the truck bed, it can severely limit space available for other cargo, which might be a critical consideration for many users. Also, like several other options, this tank does not include a fuel transfer pump, necessitating an additional purchase and installation. Therefore, truck owners who frequently need to carry other large items in their bed or those seeking an integrated, ready-to-use fuel transfer system should carefully assess if the trade-off in bed space and the need for separate pump acquisition align with their operational requirements.
- Features heavy-duty aluminum construction with a clear powder coat finish.
- Generous 100 gallon capacity for extended fuel range or equipment supply.
- Compatible with diesel, gasoline, kerosene, and methanol.
Pros: Exceptional capacity for demanding applications.; Aluminum construction offers good balance of weight and durability.; Multi-fuel compatibility adds to its versatility.
Cons: Large footprint occupies a significant portion of the truck bed.; Does not include a pump, requiring an additional purchase and installation.
6. Delta PRO Series 40 Gallon Steel Transfer Tank: Value-Oriented Steel Option
The Delta PRO Series 40 Gallon Steel Transfer Tank offers a sturdy solution for fuel transfer, particularly appealing for its heavy-duty 14 gauge steel construction. In our evaluation, this material provides excellent resistance to punctures and impacts, making it a durable choice for demanding work environments. The inclusion of internal baffles is a significant safety and handling feature, based on owner feedback, as it helps to minimize fuel sloshing during transit, improving vehicle stability. Its compatibility with multiple fuel types adds to its practical value.
However, the inherent properties of steel present some limitations. While strong, steel is considerably heavier than aluminum, which can reduce the available payload capacity of a truck and potentially affect fuel efficiency. More importantly, steel tanks are vulnerable to rust if the protective finish is compromised through scratches or prolonged exposure to moisture. This requires vigilant maintenance and touch-ups to prevent corrosion from affecting the tank’s integrity over time. Therefore, users who prioritize lighter weight, minimal maintenance, or operate in highly corrosive environments might find aluminum tanks to be a more suitable, albeit potentially higher-cost, alternative.
- Constructed from heavy-duty 14 gauge steel for rugged applications.
- Internal baffles designed to reduce sloshing and increase tank stability.
- Compatible with diesel, gasoline, and kerosene fuels.
Pros: Durable steel construction offers high resistance to punctures and impacts.; Internal baffles improve handling by minimizing fuel movement.; Multi-fuel compatibility provides good versatility.
Cons: Steel is susceptible to rust if the finish is damaged.; Heavier than aluminum tanks, impacting payload capacity.
7. ATT Auxiliary Fuel Tank (Aluminum, 50 Gallon, L-Shaped): Budget-Friendly Aluminum
The ATT Auxiliary Fuel Tank, in our comparison, presents a more budget-friendly option for those seeking an aluminum L-shaped fuel box. Its 0.125 inch thick aluminum construction offers a good balance of durability and reduced weight compared to steel alternatives, which is beneficial for maintaining payload capacity. The L-shaped design, based on common configurations, provides flexibility for truck bed organization, potentially allowing for a toolbox to be mounted above the shorter section, and it includes basic safety features like a vented cap.
However, a key limitation, based on aggregated owner feedback, is that the overall build quality may not consistently match that of more premium brands. While functional, some users have reported minor inconsistencies in welding or finish, which could potentially impact long-term durability or aesthetics compared to higher-priced options. Also, this tank is primarily designed for diesel fuel, restricting its utility for those who need to transport gasoline or other fuel types. Therefore, users prioritizing absolute top-tier construction quality, extended warranty support, or multi-fuel compatibility might find investing in a higher-end brand more reassuring, even if it comes at a greater cost.
- Constructed from 0.125 inch thick aluminum for decent durability and lighter weight.
- L-shaped design allows for some truck bed versatility.
- Vented cap and internal baffling for safer fuel transport.
Pros: Lighter weight due to aluminum construction.; L-shaped design offers flexibility for truck bed organization.; More accessible option for those seeking an aluminum tank.
Cons: Build quality may not match premium brands, based on some feedback.; Primarily designed for diesel, limiting fuel type versatility.
Frequently Asked Questions
What is the difference between an auxiliary fuel tank and a transfer tank?
An auxiliary fuel tank is designed to be plumbed directly into your truck’s main fuel system, extending its driving range automatically. A transfer tank, on the other hand, is intended for transporting fuel to refuel other equipment or vehicles, typically requiring a separate pump or gravity feed system to dispense fuel.
Are fuel boxes for trucks legal?
The legality of fuel boxes depends on local, state, and federal regulations, particularly regarding capacity, fuel type, and how they are mounted and vented. Most auxiliary and transfer tanks must comply with DOT (Department of Transportation) standards and potentially specific regulations like Title 49 CFR for hazardous materials. Always verify the specific requirements in your jurisdiction and ensure the tank is properly installed and secured.
What material is best for a truck fuel box, aluminum or steel?
Both aluminum and steel have advantages. Aluminum tanks are lighter, resistant to rust, and often have a cleaner appearance. Steel tanks are generally more impact-resistant and can be less expensive. The best choice depends on your priorities: aluminum for weight savings and rust resistance, or steel for ruggedness and potentially lower cost, with the understanding that steel requires a good coating to prevent rust.
Do I need a pump for my fuel box?
For transfer tanks, a pump is almost always necessary to efficiently dispense fuel into other equipment or vehicles. Some auxiliary tanks designed to feed directly into your truck’s main fuel system may not require a separate pump, but rather a gravity feed kit or an electronic transfer module. Always check the product specifications to see what accessories are included or required.
How do I ensure safe installation of a fuel box?
Safe installation involves securing the tank properly to prevent movement, ensuring adequate venting to prevent pressure buildup, and correctly plumbing it into your truck’s fuel system (if applicable) or setting up a safe transfer method. Always follow the manufacturer’s installation instructions precisely. For complex installations, especially those involving direct integration with your truck’s fuel system, professional installation is strongly recommended to ensure compliance with safety standards and prevent leaks or other hazards.
Our Verdict
After extensive research and comparison, the Dee Zee DZ91757 Auxiliary Fuel Tank emerges as our Top Pick for its strong aluminum construction, thoughtful L-shaped design, and consistent reliability, making it an excellent choice for diesel users needing extended range. For those prioritizing overall durability and a dedicated diesel solution, the RDS Manufacturing 72740 Auxiliary Diesel Fuel Tank is a strong runner-up, offering similar quality with the added convenience of a manual sight gauge.
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