If you need serious driving range for long hauls, off-road expeditions, or towing, a 40 gallon gas tank can be a game changer. We researched and compared the most popular 40 gallon fuel tanks on Amazon, evaluating manufacturer specs, safety certifications, and aggregated owner reviews. Our picks include replacement tanks, auxiliary tanks, and transfer flow units for diesel and gas vehicles. Each product is scored based on performance, durability, value, ease of installation, and safety. Here are our findings.
| Photo | Product | Score | Buy |
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Transfer Flow 40 Gallon Replacement Fuel Tank Best Overall Replacement Tank Fits select Ford F-250/F-350 Super Duty (1999-2022), 40 gallon capacity, steel construction, includes sending unit |
9.1 | 🛒 Check Price |
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S&B Filters 40 Gallon Fuel Tank Best for Diesel Trucks Fits Dodge Ram 2500/3500 (2003-2012), 40 gallon, cross-linked polyethylene, includes fuel pick-up module |
8.7 | 🛒 Check Price |
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Titan Fuel Tanks 40 Gallon Auxiliary Tank Best Auxiliary Tank for Trucks Universal fit for pickup trucks, 40 gallon capacity, steel with powder coat, includes pump and hardware |
8.4 | 🛒 Check Price |
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RDS Manufacturing 40 Gallon Square Fuel Tank Best Budget Pick Square shape, 40 gallon, steel, for bed mounting, includes cap and mounting brackets |
7.8 | 🛒 Check Price |
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LRA Long Range Automotive 40 Gallon Fuel Tank Best for Jeep Wrangler Fits Jeep Wrangler JK/JL (2007-2022), 40 gallon, aluminum, includes skid plate |
8.1 | 🛒 Check Price |
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Northern Tool + Equipment 40 Gallon Transfer Tank Best for Work Trucks Rectangular, 40 gallon, steel, for bed or trailer, includes manual pump |
7.3 | 🛒 Check Price |
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Aero Tanks 40 Gallon Fuel Cell Best for Racing/Performance Universal fuel cell, 40 gallon, aluminum, foam-filled, with mounting straps |
7.6 | 🛒 Check Price |
1. Transfer Flow 40 Gallon Replacement Fuel Tank: Best Overall Replacement Tank
The Transfer Flow 40 gallon replacement tank is designed to directly replace the factory fuel tank on select Ford Super Duty trucks. In our evaluation, this tank stands out for its straightforward installation and robust steel construction. Owner feedback consistently highlights the ease of installation and the significant range increase. The tank includes a new sending unit and all necessary hardware, making it a complete kit.
However, this tank is not universal; it only fits certain Ford models (1999-2022 F-250/F-350). Also, the steel construction adds weight compared to some plastic alternatives. If you drive a compatible Ford and want a hassle-free upgrade, this is our top pick. But if you own a different make or prefer a plastic tank for weight savings, you should consider other options.
- Direct replacement for factory tank, no modifications needed
- Heavy-duty steel with anti-corrosion coating
- Includes fuel level sending unit and tank straps
Pros: Bolts in place of stock tank with minimal effort; Increased range without losing cargo space; Transfer Flow is a trusted brand in fuel systems
Cons: Only fits specific Ford models, not universal
2. S&B Filters 40 Gallon Fuel Tank: Best for Diesel Trucks
The S&B Filters 40 gallon tank is engineered for diesel Ram trucks, offering a lightweight polyethylene alternative to steel. According to manufacturer specs, the rotomolded construction resists corrosion and impact better than some steel tanks. In our research, we found that owners appreciate the integrated fuel pick-up module which simplifies installation. The tank is designed to maximize ground clearance while adding capacity.
On the downside, this tank only fits Ram 2500/3500 models from 2003-2012, and some owners reported that the fitment may require minor trimming for certain years. It is also not ideal for gasoline engines. If you own a diesel Ram and want a corrosion-proof upgrade, this is a strong choice. Skip it if you drive a gas truck or a different brand.
- Rotomolded polyethylene resists corrosion and dents
- Designed for diesel trucks with integrated pick-up module
- Includes all installation hardware and instructions
Pros: Lightweight and durable plastic construction; Specifically engineered for diesel applications; Easy to install with detailed instructions
Cons: Limited vehicle fitment (Ram only); May require slight modification for some model years
3. Titan Fuel Tanks 40 Gallon Auxiliary Tank: Best Auxiliary Tank for Trucks
The Titan Fuel Tanks auxiliary tank is a universal solution for adding 40 gallons of fuel capacity in the bed of a pickup. Our evaluation of the specs shows a steel tank with a durable powder coat finish that resists rust. The included 12V transfer pump lets you move fuel to the main tank on demand. Based on owner feedback, the tank is solid and the pump works reliably, though installation is more involved than a direct replacement.
The main drawback is that it occupies bed space, which may be a deal-breaker for those who need the bed for cargo. Also, wiring the pump requires basic electrical knowledge. If you have a truck and need extra range for towing or off-roading without modifying the factory tank, this is a good option. Skip it if you need to keep your bed clear.
- Universal design fits most full-size pickup beds
- Heavy-duty steel with black powder coat finish
- Comes with 12V transfer pump and installation kit
Pros: Can be used with gas or diesel; Pump allows easy transfer to main tank; Sturdy construction with protective coating
Cons: Takes up bed space; Installation may require drilling and wiring
4. RDS Manufacturing 40 Gallon Square Fuel Tank: Best Budget Pick
The RDS Manufacturing square tank is a no-frills option for those seeking a budget-friendly 40 gallon fuel tank. According to the spec sheet, it is made of steel with a red powder coat finish and comes with a cap and brackets. In our comparison, this tank offers the most value for the price, but it lacks features like a sending unit or pump. Owner reviews note that it works well for stationary storage or as a gravity-fed tank.
However, it is not designed for direct vehicle integration; you will need to add your own pump and fittings. The square shape may be awkward to mount in some truck beds. If you need a simple, low-cost tank for fueling equipment or as a reserve, this is a solid choice. Skip it if you want a seamless, pump-ready auxiliary system.
- Simple square design fits many applications
- Steel construction with red powder coat
- Includes fuel cap and mounting hardware
Pros: Affordable price point for 40 gallon capacity; Versatile mounting options (bed or trailer); RDS has a long history in fuel tanks
Cons: No pump included; Basic design may not fit all trucks without modification
5. LRA Long Range Automotive 40 Gallon Fuel Tank: Best for Jeep Wrangler
The LRA Long Range Automotive tank is purpose-built for Jeep Wrangler enthusiasts who need extra fuel for remote trails. We researched the specs and found that the aluminum construction keeps weight down while the included skid plate protects the tank from rocks. Owner feedback indicates that installation is straightforward and the tank fits well without modifications. It is a favorite among overlanders.
The main limitation is that it only fits Jeep Wrangler JK and JL models (2007-2022). Also, the price is higher than many steel tanks. If you own a Wrangler and prioritize off-road durability and range, this is an excellent investment. Skip it if you drive a different vehicle or are on a tight budget.
- Aluminum construction saves weight
- Includes heavy-duty skid plate for off-road protection
- Direct fit for Jeep Wrangler with no cutting required
Pros: Significantly increases range for off-road adventures; Lightweight aluminum resists corrosion; Comes with skid plate for trail protection
Cons: Only fits Jeep Wrangler (JK/JL); Premium pricing compared to steel tanks
6. Northern Tool + Equipment 40 Gallon Transfer Tank: Best for Work Trucks
The Northern Tool transfer tank is a utilitarian option for job sites where you need to fuel equipment. According to the product details, it comes with a rotary hand pump, making it independent of power sources. In our evaluation, the tank is functional but basic. Owner reviews mention that it is heavy when full and the manual pump can be slow, but it gets the job done for occasional use.
The downsides are the lack of an electric pump and the paint finish that may not hold up to harsh conditions. It is also not designed for permanent vehicle installation. If you need a simple, affordable tank for fueling generators or machinery, this works. Skip it if you want a seamless in-vehicle fuel system.
- Rectangular shape fits tight spaces
- Steel with black paint finish
- Includes rotary hand pump for manual transfer
Pros: Low cost per gallon; Manual pump works without electricity; Sturdy steel build
Cons: No electric pump, slow transfer; Paint finish may chip over time
7. Aero Tanks 40 Gallon Fuel Cell: Best for Racing/Performance
The Aero Tanks fuel cell is built for performance applications where fuel starvation during hard cornering is a concern. The manufacturer specifies aluminum construction with internal foam to minimize slosh. In our research, this tank is popular among racers and off-road enthusiasts who need a reliable fuel supply under extreme conditions. Owner feedback praises the build quality and the foam baffling.
However, it is a bare cell: no sending unit, no pump, and no installation kit. You will need to source additional components and fabricate mounting. It is also more expensive than many standard tanks. If you are building a race truck or a high-performance off-road rig, this is a top choice. Skip it if you want a simple bolt-in replacement.
- Aluminum construction with internal foam baffling
- Designed for racing or high-performance applications
- Includes mounting straps and outlet fittings
Pros: Foam baffling reduces fuel slosh; Lightweight and corrosion-resistant; Compatible with fuel injection systems
Cons: No sending unit or pump included; Requires custom installation and plumbing
Frequently Asked Questions
What vehicles can use a 40 gallon gas tank?
40 gallon tanks are most commonly used in full-size pickup trucks like Ford F-Series, Ram 2500/3500, and Chevrolet/GMC Silverado/Sierra. Some auxiliary tanks are universal and can be mounted in the bed. Always check the manufacturer’s fitment guide for your specific vehicle year and model.
Is it safe to install a larger fuel tank?
Yes, when installed correctly and using tanks that meet industry standards (such as DOT or CARB compliance). Ensure all connections are secure, the tank is properly vented, and electrical components are fused. If you are not experienced, professional installation is recommended.
Do I need a pump for an auxiliary tank?
Most auxiliary tanks include a pump (electric or manual) to transfer fuel to the main tank. Some replacement tanks use the vehicle’s existing fuel system. If you choose a tank without a pump, you will need to add one or use gravity feed if the tank is mounted higher.
Will a 40 gallon tank affect my vehicle's performance?
The added weight of fuel (about 240 pounds for 40 gallons of gasoline) can slightly reduce acceleration and fuel economy, but the effect is usually minimal. The increased range often outweighs the small performance hit for long-distance drivers.
Can I use a 40 gallon tank for diesel?
Many 40 gallon tanks are compatible with both gasoline and diesel, but some are specifically designed for diesel (e.g., with different pickup modules). Always check the manufacturer’s specifications to ensure compatibility with your fuel type.
Our Verdict
After researching and comparing the top 40 gallon gas tanks, our top pick is the Transfer Flow 40 Gallon Replacement Tank for its easy installation and robust construction on compatible Ford trucks. For diesel Ram owners, the S&B Filters tank is a close runner-up due to its lightweight polyethylene design and integrated pick-up module. Choose based on your vehicle fitment and whether you need a replacement or auxiliary system.
