Combo Toolboxes

Tool ‘N” Fuel

Dual-purpose combo boxes maximize bed space and increase utility value

Work truck bed space is always at a premium, and lockable storage is even more valuable. Having quick access to spare fuel is also nice, especially for smaller companies with just a couple pieces of equipment in the field.

So, contractors who need to carry spare fuel for construction and landscaping equipment, along with tools, oil, straps, chains and other small items used around a jobsite, find a bed-mounted combination toolbox/fuel tank an extremely attractive addition to their rolling office.

Today’s selection of bed-mounted combo tanks provide double, triple or even quadruple the capacity of the truck’s fuel tank, with capacities ranging from 30 to 100 gallons. Those extra gallons of fuel in the bed of your pickup can provide a full day’s worth of work out of smaller equipment without wasted downtime making a fuel run.

Choosing which tool-and-fuel combo box is best for your needs is as much a matter of personal preference as it is design.

Combo boxes are designed to fit neatly between a pickup’s wheel wells. Diamond-plate aluminum has become a popular material choice for its strength-to-weight ratio and its good looks. (Photo courtesy of Transfer Flow)

Bed-mounted fuel tanks come in two distinct types: auxiliary and transfer tanks. (Tanks are built task-specific; one should never be set up to do the job of the other.)

The most common are transfer tanks, which require an external pump, hose and nozzle to transfer fuel from the bed-mounted tank to secondary equipment or to “refuel” the truck itself.

These tanks are generally restricted to noncombustible liquids – meaning no gasoline – and are most often used for diesel fuel. They can also be used to carry liquid fertilizers, nonpotable water and the like.

Some refuel tank designs place the neck and pump mechanism outside the box for fulltime access. Toolbox lid designs include single, double and special designs to accommodate other bed-mounted equipment. (Photo courtesy of RDS)

The second type of bed-mounted fuel tank available with toolbox combinations is the auxiliary tank. These tanks are generally plumbed into the vehicle’s factory fuel system, essentially acting as a second tank for the vehicle. Some versions allow the option of an external pump, hose and nozzle for refueling of off-board equipment.

Combination units bolt into the bed of the pickup using welded-on brackets or anchor plates. Most boxes include mounting kits that contain all required hardware along with installation instructions. (Photo courtesy of Daws Manufacturing)

The toolbox fixtures are the same as those used on standard box configurations and include paddle or “T”-handles and pushbutton or flush-mounted key locks.

Most auxiliary tanks include a dash-mounted switch that allows the operator to select which tank the truck draws fuel from, and the factory in-dash fuel gauge monitors the tank that is currently in use.

What you don’t want to do is jerry-rig a transfer tank so it acts as an auxiliary fuel tank. Doing so creates your own business insurance and liability issues along with warranty issues with most fuel tank manufacturers.

“We know customers do this, but if they do this with one of our tanks, it voids the warranty,” warns Chris Schiphof, vice president of sales at Tradesman Truck Accessories, a builder of fuel transfer tanks and toolboxes since the early ‘70s. “We can’t be liable for any engines, and that is why we stress the customer buy an auxiliary tank if that is what they need.”


Tool/fuel combos are available in aluminum, steel or aluminized-steel versions. Aluminum is lighter and won’t rust; steel is generally heavier and stronger. Diamond-plate aluminum has become an extremely popular choice because of its strength-to-weight ratio and because the material retains its appearance longer than other types.

Some tool/fuel combos are designed as a single unit, with the tank built as an integral part of the whole. Other units are built using an “L”-shaped fuel tank with a rectangular toolbox either welded to or sitting atop the foot of the “L.” (Standard fuel capacities for integrated toolbox/fuel tank combinations range from 30 to 60 gallons, while “L”-tanks typically provide 50 to 100 gallons.)

Both types serve the same purpose but the integrated units offer a seamless appearance, while the two-piece allows the option of changing the tool box or fuel tank at will.

Toolboxes integrated with a fuel tank are reasonably roomy, with typical capacities ranging from about 5 to 10 cubic feet of storage. If maximum cargo capacity is a goal, look to the “L”-tank design because those toolboxes are standard capacity.

A variety of combination designs allow for the toolbox section to open with a single lid, double lids (also called gullwing lids) and units to accommodate fifth-wheel and gooseneck trailer hitches. Some toolbox/fuel tank manufacturers offer custom units designed and built to meet unique bed or tool configurations.

Some refuel designs place the filler neck and pump within the toolbox so that they are protected when the box is locked; other designs have the filler and pump outside the box for fulltime access.


Another item to look for when buying a tank of either type is it being designed with internal baffles, which are used to prevent fuel from sloshing excessively while cornering, preventing any adverse affect on your pickup’s handling. This is especially helpful in tanks carrying more than 50 gallons.

The fuel pickup location is also important. If the pickup point is not from the top of the tank, ensure that a lower point is fully protected from being accidentally dislodged, allowing the fuel to leak and creating environmental and safety hazards.

It’s also good to have fuel gauge in either style tank to provide accurate information as to how much fuel remains.

And before you order that toolbox/tank combo it’s prudent to double-check the measurement of the bed box carefully to make sure that the tank you are ordering will fit without interference – or interfere with the gooseneck mounting location.

Selecting a tool/fuel combo box is a good business investment. Efficient use of a pickup is always a benefit to a professional operation, and the ability to transport sufficient fuel and tools in the bed adds value to these two-in-one systems.


Auxiliary tanks may use the truck’s fuel pump or require a 12-volt electric pump, while transfer tanks require either an electric or a hand pump that’s not usually included with the tank itself.

Every tank manufacturer or retailer will be able to recommend a pump that provides sufficient flow and includes a hose of sufficient length to suit the application. Some are also available with flow gauges with which to keep track of the tank’s fill level and how much fuel is dispensed.

Automatic shut-off nozzles are a convenient feature and should definitely be considered, because they prevent overfilling and allow the user to attend to other chores while transferring fuel.

The two best-known auxiliary fuel and transfer pump manufacturers are Great Plains Industries (; 800-835-0113) and Fill-Rite, a subsidiary of Tuthill (; 800-634-2695). Both companies supply electric and hand pumps designed specifically for use with transfer and auxiliary tanks.

Consult with your tank manufacturer or retailer for equipment recommendations that are compatible with the tank you purchase. —S.C.


American Tank

Combination toolbox and auxiliary fuel systems from American Tank feature secure and easy-to-operate handles, heavy-duty latches and locking systems, fully crested lids and heavy-duty gas lid supports. The units are constructed of 1/8-inch 3003 marine-grade diamond-plate aluminum with a triple baffle in the fuel tank. This tool/fuel combination features a height of 19 inches so as not to interfere with fifth wheel or gooseneck trailers.; 940-686-2391

Better Built

Better Built offers baffled 75-gallon combination transfer tanks/toolboxes for easy transportation of nonflammable liquids such as diesel fuel or water. Available in either .125-inch tread-plate aluminum or 12-gauge steel, the units offer lockable caps and couplers, and dual flush-mounted 2-inch reinforced bungs. The pump mounting location is reinforced, and a mounting kit is included for securing the unit to the truck bed with fully welded mounting brackets.; 800-366-8289

Dee Zee

Dee Zee’s combo transfer tanks are available in either Brite-Tread aluminum or 14-gauge steel. The tanks feature three baffles, cap, drainage plug and coupler for venting. A radius curve design eliminates key welded pressure points, and the utility chests offer stainless paddle handles, dampened gas shocks, closed-cell foam gaskets and a double-V lid stiffener. Available in either uncoated or gloss black powdercoat, and the steel varieties come in white or black powdercoat featuring NRT rust-inhibiting technology.; 800-779-8222

Delta Consolidated Industries

Delta’s combo transfer tank features a 74-gallon capacity built with .125 tread-plate aluminum and includes two center baffles for added strength. Two 2-inch NPT-reinforced bungs allow for reversing the lockable filler cap for access from either side, and welded tie-down brackets secure the tank in the truck bed. The removable storage chest features a self-rising lid with two heavy-duty gas spring lifts and adjustable heavy-duty lid strikers.; 800-643-0084

Highway Products

Highway Products manufactures both standard and custom combination transfer tanks and toolboxes. The transfer tanks can be built into fifth wheel boxes, single-lid boxes or gullwing boxes in 50-, 55-, 66-, 80- and 90-gallon capacities for diesel fuel only. The lockable combo units feature 3/16-inch marine-grade aluminum construction and are secured to the truck bed with “J”-bolts.; 800-866-5269

KSH Marine

KSH toolbox/tank combos come in standard sizes of 40-, 45-, 60-, 65- and 98-gallon capacities and are designed to be bed height. The DOT-approved tanks can be used as either an auxiliary diesel (or gas) fuel tank or a fuel transfer tank. The tanks are made of .125-gauge mill finish aluminum. The toolbox sides are made of .063 aluminum diamond-plate with a lid of .125 aluminum diamond plate. The aluminum fuel tank is made with two baffles to control fuel sloshing and to provide added strength. The combo has a keyed double lock to secure items in the toolbox section and limit access to the fuel fill neck of the auxiliary tank.; 928-680-6610


RDS manufactures both auxiliary and transfer tanks in combination with toolboxes. The fuel can gravity feed from the bottom of the tank or an optional diesel installation kit can be used to economically and easily connect the tank to the vehicle’s OEM fuel tank. Gasoline auxiliary fueling is also possible if the fuel is siphoned from the top of the tank using an electric fuel pump. RDS transfer tanks have a structurally reinforced 2-inch FTP coupling for installing a hand or electric fuel pump and can also be set up for auxiliary fueling.; 800-292-6898

Taylor Wings

This Taylor Wings toolbox and auxiliary fuel tank for nonflammable liquids combines a 90-gallon tank and toolbox in a compact 48-by-31-by-24-inch size that fits all full-size pickups. The unit features diamond-plate aluminum construction with a full automotive weather seal and stainless-steel paddle latches. It is compatible with a GPI TP9 transfer pump and auto fuel controller system. The tank includes a 5/16-inch-thick polymer lining and a 12-month warranty on both parts and labor.; 800-634-7757

Tradesman Truck Accessories

Tradesman combination toolbox/transfer fuel tanks, fabricated from .100 gauge aluminum or 16-ga steel, are intended for nonflammable liquids only. The tanks are available in an 80-gallon version for short-bed Chevy and Ford trucks or a 90-gallon version for all long-bed, full-size trucks. They feature lockable vent caps, and bolt packages are available for securing the tank to the truck bed. The toolbox is fitted with a three-finger paddle handle and double latch system with a keyed lock.; 866-789-5300

Transfer Flow

Transfer Flow’s auxiliary and transfer combos come in 30-, 40- and 50-gallon capacities in either diamond-plate aluminum or aluminized steel. They are DOT approved for both gasoline and diesel pickups, including Dodge, Ford, GM and Toyota Tundra trucks. These all-in-one auxiliary refuel toolbox combos come with all components needed for installation (some Ford and GM vehicles require a fill-neck adapter kit) and should not interfere with most standard in-bed hitches. Available options include a riser kit, allowing storage under the tank, and a refueling conversion kit for fuel transfer.; 800-442-0056

UWS, a Division of Thule

Thule manufactures a variety of toolboxes, tanks and combination units under the UWS brand. The combination liquid transfer tank/tool box shown features an 85-gallon volume and measures 48-by-27-by-24 inches. The fully welded one-piece tub is fabricated from heavy-duty .125 aluminum alloy with a commercial-grade vented cap and mounting flanges and stainless-steel paddle handle lock. UWS offers 45- to 100-gallon transfer tanks for diesel fuel and nonpotable water in both aluminum and powder-coated steel.; 800-561-0716


Diesel is not as volatile as gasoline, and its transport is not governed by Department of Transportation (DOT) regulations. However, state regulations vary, so it’s best to consult your state’s department of motor vehicles for the rules that dictate usage in your area just to be on the safe side of the law.

For gasoline applications, the laws are much stricter. Tanks for the transportation of gasoline are governed by stringent guidelines and require a special DOT permit.