After researching manufacturer specifications, industry safety standards, and hundreds of owner reviews, we evaluated the top aux fuel tanks for truck beds. Our comparison focuses on capacity, material, transfer systems, and real-world reliability. Below are our findings to help you choose the best tank for your needs.
| Photo | Product | Score | Buy |
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Transfer Flow 50 Gallon Auxiliary Fuel Tank Best Overall 50 gallon capacity, aluminum construction, includes fuel transfer pump |
9.2 | 🛒 Check Price |
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RDS Manufacturing 40 Gallon Diesel Fuel Tank Best Value 40 gallon capacity, polyethylene construction, manual pump |
8.7 | 🛒 Check Price |
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Titan Fuel Tanks 30 Gallon Auxiliary Tank Best Compact 30 gallon capacity, steel construction, includes locking cap |
8.4 | 🛒 Check Price |
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Dee Zee 40 Gallon Poly Fuel Tank Lightweight Pick 40 gallon capacity, polyethylene, includes 12V pump |
8.1 | 🛒 Check Price |
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Northern Tool 30 Gallon Diesel Tank Budget Friendly 30 gallon capacity, steel, manual pump |
7.8 | 🛒 Check Price |
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Go Rhino 50 Gallon Auxiliary Fuel Tank Heavy Duty 50 gallon capacity, steel, includes mounting brackets |
7.3 | 🛒 Check Price |
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Scepter 25 Gallon Military Fuel Tank Portable Option 25 gallon capacity, polyethylene, no pump |
7.0 | 🛒 Check Price |
1. Transfer Flow 50 Gallon Auxiliary Fuel Tank: Best Overall
In our evaluation, the Transfer Flow 50 gallon tank stands out for its robust aluminum construction and integrated pump. Owner feedback highlights its leak-free design and compatibility with both diesel and gas. The tank meets DOT safety standards, and the pump includes an automatic shutoff to prevent overfills.
However, this tank is a significant investment. If you only need occasional extra fuel and have a tight budget, a poly tank may be more cost-effective. Also, the 50 gallon size may be overkill for short trips, and the weight when full can affect payload.
- 50 gallon capacity for extended range
- Aluminum construction resists rust and corrosion
- Integrated 12V pump with automatic shutoff
Pros: Excellent build quality and fit; Easy installation with included hardware
Cons: Premium pricing
2. RDS Manufacturing 40 Gallon Diesel Fuel Tank: Best Value
Based on owner feedback and the spec sheets, the RDS 40 gallon tank offers excellent value for the price. The rotomolded polyethylene is durable and UV resistant, and the tank fits most truck beds without modification. The manual pump is simple and reliable, though it requires effort for large transfers.
If you need a powered transfer system or plan to fill large equipment quickly, the manual pump may be a drawback. Also, the polyethylene can be susceptible to scratches, but it remains a solid choice for budget-conscious buyers.
- 40 gallon capacity in a compact footprint
- Rotomolded polyethylene for impact resistance
- Manual pump included (no electrical required)
Pros: Affordable price point; Lightweight and easy to handle
Cons: Manual pumping can be slow
3. Titan Fuel Tanks 30 Gallon Auxiliary Tank: Best Compact
We compared the Titan 30 gallon tank and found it ideal for those who want extra fuel without sacrificing too much bed space. The steel construction is strong, and the powder coat helps resist corrosion, but owners note that scratches should be touched up to prevent rust. The locking cap adds peace of mind.
If you need more than 30 gallons or prefer a lighter poly tank, this may not be the best fit. Also, the tank does not include a pump, so you’ll need to purchase one separately or use gravity feed.
- 30 gallon capacity for moderate range extension
- Heavy-duty steel with powder coat finish
- Locking fuel cap for security
Pros: Compact size leaves room for other gear; Sturdy steel construction
Cons: Steel can rust if scratched
4. Dee Zee 40 Gallon Poly Fuel Tank: Lightweight Pick
Based on owner feedback and the spec sheets, the Dee Zee poly tank is a good balance of capacity and weight. The 12V pump transfers fuel quickly, and the tank is easy to install alone. However, some users reported slight warping in very hot climates, so it may not be ideal for desert use.
If you need a tank for extreme temperatures or heavy off-road use, a metal tank might be more durable. But for most users, this offers a reliable and lightweight solution.
- 40 gallon capacity with integrated 12V pump
- Lightweight polyethylene for easy installation
- Includes fill hose and vent kit
Pros: Lightweight compared to steel tanks; Integrated pump works well
Cons: Polyethylene can deform under extreme heat
5. Northern Tool 30 Gallon Diesel Tank: Budget Friendly
In our evaluation, the Northern Tool 30 gallon tank is a no-frills option for those on a tight budget. The steel tank is functional, and the manual pump works, but owner feedback notes that the enamel coating can chip, leading to rust. It’s best for occasional use in dry climates.
If you need a tank for daily use or in humid environments, consider a poly or powder-coated steel tank. Also, the 30 gallon capacity may be limiting for long hauls.
- 30 gallon capacity at an entry-level price
- Steel construction with enamel finish
- Manual rotary pump included
Pros: Very affordable; Simple, no-frills design
Cons: Enamel finish can chip over time
6. Go Rhino 50 Gallon Auxiliary Fuel Tank: Heavy Duty
Based on owner feedback and the spec sheets, the Go Rhino 50 gallon tank is built for serious off-road and work use. The steel construction and mounting brackets are robust, but the tank’s weight when full (over 400 lbs) significantly reduces payload. Some owners also reported fitment issues with certain truck models.
If you have a heavy-duty truck with high payload capacity and need maximum fuel, this tank works. However, for lighter trucks or those who need to carry other cargo, the weight and size may be prohibitive.
- 50 gallon capacity for maximum range
- Steel with black powder coat
- Includes heavy-duty mounting brackets
Pros: Large capacity; Strong mounting system
Cons: Very heavy when full
7. Scepter 25 Gallon Military Fuel Tank: Portable Option
We researched the Scepter 25 gallon tank and found it best as a portable fuel storage solution rather than a dedicated truck bed tank. It is designed to be moved and stacked, but it lacks a pump and mounting system. Owner feedback indicates it works well for storing fuel and transferring with a siphon, but it’s not ideal for permanent installation.
If you need a fixed aux tank with easy dispensing, look elsewhere. This tank is better for those who want to store fuel cans and move them as needed. Safety ratings are lower due to the lack of a secure mounting system.
- 25 gallon capacity for portable use
- Military-spec rotomolded polyethylene
- Stackable design for storage
Pros: Very portable and stackable; Durable construction
Cons: No pump included
Frequently Asked Questions
Are aux fuel tanks safe in a truck bed?
Yes, when properly installed and certified. Look for tanks that meet DOT or CARB standards. Ensure the tank is securely mounted and that the fuel system is leak-free. Use the correct type of fuel for your engine (diesel or gas).
Do I need a pump for an auxiliary fuel tank?
It depends on the tank. Some come with integrated or included pumps (manual or 12V). Others require you to purchase a pump separately or use gravity feed. For convenience, a 12V electric pump is recommended for quick transfers.
Will an aux fuel tank affect my truck's warranty?
Generally, aftermarket fuel tanks do not void the vehicle warranty, but any damage caused by improper installation may not be covered. It is best to check with your dealer and ensure professional installation.
How do I choose between steel and polyethylene tanks?
Steel tanks are more durable and resistant to impact but can rust if the coating is damaged. Polyethylene is lighter and rust-proof but can deform under extreme heat or UV exposure. Choose based on your climate and usage.
What capacity aux fuel tank should I get?
Consider your typical range needs and payload capacity. A 30-40 gallon tank is common for most users. Larger tanks (50+ gallons) add significant weight and may require a heavy-duty truck.
Our Verdict
After researching and comparing, our top pick is the Transfer Flow 50 Gallon Auxiliary Fuel Tank for its superior build quality, safety features, and integrated pump. For best value, the RDS Manufacturing 40 Gallon Diesel Fuel Tank offers reliable performance at a lower price point.
