Our readers keep the lights on and my morning glass full of iced black tea. As an Amazon Associate, I earn from qualifying purchases.9 Best Additional Fuel Tank | Rig Your Truck the Smart Way

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The TITAN 5410050 is a 50-gallon rotational-molded HDPE tank engineered to sit low in the truck bed, fitting cleanly under most fiberglass and roll-up tonneau covers. Weighing 68 pounds empty, it’s light enough for a single person to maneuver into position, and the unit ships with a complete install kit that includes a 12V pump, wiring harness, and mounting brackets. Real-world owners report saving between and per gallon by filling up at station pumps instead of highway diesel islands, with the tank paying for itself in roughly two years of regular towing.

The integrated 12V pump delivers steady flow, though some users note it runs slower than a dedicated Fill-Rite unit. The vent adapter design has drawn criticism for lacking a positive barb to keep the vent tube seated—adding a zip tie or replacing the clamp solves the issue during installation. The fill cap is lockable, and the tank includes a rollover valve for safety. TITAN provides a 30-day warranty, and several owners report excellent customer service when they received a faulty pump.

For a fifth wheel or travel trailer owner who wants 150–200 extra miles of range without sacrificing bed space or adding a bulky steel rectangle, this tank is the gold standard. The HDPE construction will never rust, and the low-profile shape means you keep full use of the rear of the bed for other gear. Gauge recalibration via Forscan is needed on newer Ford trucks to see the additional fuel on the dash cluster.

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This TITAN replaces the factory 34-gallon diesel tank on 2017-2024 Ford F-250 and F-350 crew cab short beds with a 55-gallon HDPE unit that uses the truck’s own sending unit, fuel lines, and in-tank pump. The 21-gallon increase translates to roughly 300 extra highway miles—enough to drive from Denver to Salt Lake City on a single tank. The tank fits without interfering with power steps, air bag systems, or aftermarket lift pumps, and the mid-ship mounting position maintains the truck’s factory ground clearance.

Installation runs about two hours with a helper, but some 2017-2019 models require a Forscan tool or dealer visit to recalibrate the dash cluster’s distance-to-empty readout so the gauge reads past the stock tank level. TITAN includes all necessary hardware, though a few owners report missing bolts due to shipping damage. The tank is compatible with Fleece, AirDog, and FASS aftermarket filtration systems, making it a solid base for a full fuel system upgrade.

For the Ford Super Duty owner who tows heavy and wants the most seamless integration—no extra pump, no transfer hoses, no bed space lost—this is the definitive drop-in solution. The only tradeoff is losing the factory FX4 skid plate, but the tank’s HDPE construction is tough enough to handle gravel roads and occasional debris strikes.

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RDS’s 72771 is a fully welded aluminum tank rated at 60 gallons, though real-world users report a usable capacity of roughly 57 gallons after accounting for the pump shut-off. Aluminum construction means zero corrosion—no paint chips, no rust flakes entering your fuel system over time. The rectangular profile measures 55 x 20 x 12.75 inches, making it one of the slimmest high-capacity tanks for sliding under a hard tonneau cover on long-bed trucks.

The tank ships with a locking automotive-style fill cap and a universal mounting design that accepts standard install kits. Users on 2010-era Ford and Ram trucks report a straightforward install with two people, though the fill valve inlet can be tight on models with factory bed liners. RDS recommends pairing the tank with their install kit, which includes the filler neck, hoses, and brackets needed to complete the job. A few owners note that the tank’s 60-gallon rating is optimistic—the automatic shut-off on most pumps stops at 52 gallons, and only another 5 gallons can be added slowly after foam settles.

For diesel truck owners who want the largest possible capacity without rust risk and who plan to mount a pump system separately, this RDS tank is a heavy-duty choice. The flat top profile works well for stacking toolboxes or aux batteries on top, maximizing the utility of your bed space.

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The RDS 71083 is specifically designed for gasoline auxiliary fueling—its aluminum construction meets the material standards required for volatile fuels, and the design allows for an electric fuel pump to siphon from the top of the tank (gravity feed is not permitted for gasoline). At 45 gallons and 42 pounds empty, it’s remarkably light relative to its steel counterparts, and the fully welded seams ensure no leaks develop over time even with ethanol-blended fuels.

Owners report a straightforward install on Ram 2500 and 3500 long beds, with the tank fitting snugly against the front bed wall and sitting just above the rails—visible but not obstructive to rear visibility. The billet-style lockable fuel cap is a standout feature, adding a premium feel and security. RDS provides an install kit separately that includes the necessary filler tube and hardware, though cutting the fill tube to the right length requires patience and a sharp saw. A few units arrive with bent mounting tabs due to minimal packaging, but the aluminum bends back easily without damage.

This is the best pick for gasoline truck owners—especially those with 5.7L or 6.2L gas engines—who need a dedicated auxiliary tank that won’t rust out and stays compliant with gasoline safety requirements. The 45-gallon capacity adds roughly 350-400 miles of range to a typical gas half-ton.

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The Dee Zee DZ92556NSB is built from 14-gauge alloy steel and features five internal stability baffles to prevent fuel slosh and reduce stress on the welded seams during hard braking or off-road driving. At 42 gallons, it’s a mid-capacity option that fits most truck beds without protruding above the side rails—a key consideration for owners who want to retain a flush bed cover or toolbox clearance.

The tank includes mounting tabs that bolt directly to the truck bed floor, and the radius-curved corners eliminate stress concentration points that can lead to cracking over time. A drain plug at the bottom makes periodic cleaning straightforward. The steel construction is durable, but the paint finish is a common complaint—owners report chips and scratches from shipping and recommend touching up any exposed metal immediately to prevent rust. The tank is rated for both gasoline and diesel, and the lockable cap adds basic security.

For the owner who needs a no-frills, bulletproof steel tank that fits a standard short bed and works with either fuel type, the Dee Zee delivers solid value. The 42-gallon size is large enough to make a difference on long hauls but small enough to leave space for a gooseneck hitch ball or a bed tool box.

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VEVOR’s 58-gallon diesel transfer tank is a polyethylene unit with a built-in 12V electric pump rated at 10.6 GPM, making it a complete all-in-one refueling station straight out of the box. The tank uses 6-12mm thick LLDPE that resists UV radiation and impact, and the integrated duplex filtration system—a coarse inner strainer plus a fine outer filter—keeps particles out of your equipment’s fuel system. The automatic shut-off nozzle prevents overfills, a feature usually reserved for much more expensive setups.

The tank’s integrated forklift pockets and molded grooves simplify loading, and even when full it can be moved with a skid-steer or pallet jack. At 65.5 pounds empty, it’s lighter than a steel tank of equivalent capacity. However, owners report that the assembly requires thorough tightening—many fasteners arrive finger-loose, and the supplied O-ring on the pump can be too stretchy for diesel, requiring replacement with a stiffer seal. The fuel gauge is also known for being optimistic, reading higher than the actual fuel level.

For the farmer, contractor, or overlander who moves diesel between equipment and doesn’t want to piece together a tank, pump, and hose separately, the VEVOR is the most complete value package. The 58-gallon capacity and 10+ GPM flow rate make it practical for bulk refueling, though you’ll want to spend 30 minutes tightening and sealing everything before first use.

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Better Built’s 36-gallon rectangular tank is constructed from alloy steel with a gloss black finish and includes an overfill restriction valve that automatically stops the pump nozzle to prevent spillage—a small but meaningful feature when you’re trying to squeeze every gallon in quickly. Built-in baffles add structural rigidity and keep the load stable during transport, while the flush-mounted 2-inch inlet and outlet bungs allow for fast fuel transfer.

The tank measures 11 inches high, making it one of the slimmest options for sliding under a crossbed toolbox or a low-profile tonneau. Included with the tank are a vented lockable cap and a mounting kit with rubber bushings to dampen vibration. Owners caution that the tank is for diesel only, not gasoline, and the packaging has drawn repeated criticism—boxes arrive damaged, and tabs often need straightening. Welding debris inside the tank is common; flushing with diesel before first connection is recommended.

For the diesel truck owner who needs a compact, affordable tank that disappears into the bed without taking up vertical space, the Better Built 36-gallon is a smart choice. The 3-year warranty adds peace of mind that the steel build will hold up.

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The Fill-Rite FR1204H is a bung-mounted 12V rotary vane pump that moves 15 gallons per minute of diesel, gasoline, kerosene, ethanol blends, and biodiesel. The cast iron housing is heavy but thermally stable, and the rotary vane technology maintains consistent flow speed as the internal components wear—unlike cheaper diaphragm pumps that lose pressure over time. Thermal overload protection shuts the motor down before overheating damage occurs.

Installation is straightforward for anyone comfortable with basic 12V wiring: the removable junction box rotates 180 degrees for tight spaces, and the pump comes with a 3/4-inch elbow, ground wire, wire nuts, and PTFE tape. The pump pulls fuel from tank depths of 8 feet and discharges up to 37 feet of head, making it suitable for both in-bed tanks and barrels in a shop or barn. Owners consistently praise the build quality over lighter competitors, noting that Fill-Rite’s all-metal internal components outlast the plastic impellers used by cheaper brands.

If you already own a tank or plan to build a custom system, the FR1204H is the gold standard for a standalone 12V transfer pump. The lifetime warranty on the pump head is unmatched, and the 15 GPM flow rate—while slightly optimistic in real-world conditions—is fast enough to fill a 30-gallon tank in under three minutes.

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JohnDow’s JDI-FST15 is a heavy-duty welded steel tank rated at 15 gallons with a gravity-feed dispensing system that requires no pump—just elevation and the included 10-foot hose with a squeeze handle and shut-off valve. It’s UN/DOT approved for road transport of gasoline, diesel, and E85, with a ground wire and alligator clip to reduce static buildup during dispensing.

The tank is trailer-ready with bolt-mount flanges, and at 30 pounds empty it’s easy to move around. Owners love it for keeping ranch equipment, generators, and off-road vehicles fueled without trips to the station, but gravity feed is slow—one user reported it took an hour to drain 15 gallons when mounted flat on a flatbed. Elevating the front of the tank with a block speeds things up significantly. The packaging is minimal and some tanks arrive with a bent top handle or scratched paint, but the steel body and leak-free construction earn consistent praise once set up.

For the budget-conscious owner who needs a simple, no-electronics solution for occasional refueling of small equipment or weekend toys, the JohnDow 15-gallon is a reliable workhorse. Adding a cheap 12V inline pump transforms it into a much more capable system without breaking the bank.