The UWS TT-100HH-CB moves diesel and other non-flammable liquids out to the equipment that cannot come to the pump. One hundred gallons is the top of the UWS range and the point at which a transfer tank stops being a convenience and becomes the reason the truck exists. It is around 710 lb of diesel, so payload, not bed space, is usually the binding constraint. The hammerhead profile narrows the base to drop between the wheel wells and widens the upper section back out over them, which is how it keeps full capacity in a bed that a straight-sided tank of the same volume would not fit. The tool box sits on top of that. The tank is welded from .125" aluminum alloy and 100% pressure-tested before it ships, with internal baffles inside so the load does not surge forward every time you brake. The bright aluminum tread plate is the classic look, and it is more than cosmetic: bare aluminum does not rust, so there is no paint film to chip and start a corrosion problem. The built-in tool box adds 6.5ft³ of lockable, weather-sealed storage on top of the tank, using the same patented RigidCore foam-filled lid, MicroSeal gasket and stainless steel lock handles as a standalone UWS chest, so you are not giving up bed space to carry tools as well as fuel. The fill cap is a lockable commercial-grade vented unit with a reinforced collar, and the drain plug sits nearly flush with the tank floor so it actually empties. Be clear about the limits UWS puts on it, though: this is a full-size truck tank only, it will not fit a compact or mid-size truck, and it will not clear a gooseneck hitch in a short bed, where UWS recommends the 75-gallon tank instead. UWS rates this tank as DOT-compliant for transporting Class 3 combustible fuels only, such as diesel.
What's Included:
1 x UWS 100-gallon transfer tank
2 x keys for the tool box lock handles (UWS supplies keys with combo models only)
1 x filler neck and cap
1 x drain plug, 3/8"
NOT included, and you have to buy them separately: mounting hardware (UWS states you must purchase your own), an automatic shutoff nozzle, a fuel filter, a padlock for the fill cap, and any pump, hose or transfer kit
Features
100 Gallons of Usable Capacity This tank holds 100 gallons, which is about 710 lb of diesel once it is full. That is the number to plan around, not the empty weight: a full TT-100HH-CB puts roughly 860 lb into the bed before you load anything else, so check it against your truck's payload rating.
Heavy-Duty .125" Aluminum Alloy The tank is welded from .125" aluminum alloy, which is thicker than the material most transfer tanks use, and every tank is 100% pressure-tested before it ships. Aluminum also saves real weight: this one is 150 lb empty, which is payload you get to spend on cargo instead of on the tank.
Bright Aluminum Diamond-Plate Finish Bright aluminum tread plate, left bare. There is no paint film to chip, and aluminum does not rust, so weather, road salt and UV are not the problem they are for a painted steel tank.
Internal Baffles Baffles are partial walls welded inside the tank. They stop 710 lb of liquid from surging forward under braking or sideways through a corner, which is a handling and a safety issue on a loaded truck, and they add structural stiffness to the tank at the same time.
Lockable Commercial-Grade Vented Fill Cap The fill cap vents properly as the tank drains, which is what stops a tank pulling a vacuum and slowing the flow, and it has a reinforced collar and a lockable hasp so the contents are not an open invitation overnight. Bring your own padlock; UWS does not supply one.
Drain Plug Set Nearly Flush The drain plug sits nearly flush with the bottom of the tank so it actually empties, which matters if you ever switch what you are hauling or need to drop the weight before moving the tank. UWS specifies removing all liquid before relocating a tank.
Designed, Fabricated and Welded in Florida UWS states that this tank is designed, fabricated and welded at its own plant in Florida. The country of origin on record for this part is the USA.
Built-In Tool Box with 6.5ft³ of Storage The tool box is integrated into the tank rather than sitting next to it, so you get 6.5ft³ of lockable storage without giving up any more bed floor. It is built from the same aluminum as the tank.
Patented RigidCore Lid and MicroSeal Gasket The lid is two metal plates with solid foam between them, which is what keeps it from flexing, binding or warping when someone inevitably stands on it. The MicroSeal gasket seals out water and dust, and the lid self-opens to 90 degrees and self-closes, so it is a one-handed job.
Stainless Steel Lock Handles, Both Sides Stainless steel paddle handles are linked by a connecting rod so the box opens from either side of the truck, and the rod runs inside an enclosure that protects it from being bent or pried, which is the usual way a tool box lock gets defeated.
Fitment & Compatibility
Truck or Application
Fit
Full-size trucks, 3/4 ton and 1 ton (F-250/350, Ram 2500/3500, Silverado/Sierra HD)
✓ Yes, the narrowed base is designed to sit between the wheel wells
✓ Fits the bed, but check payload first: about 860 lb loaded
Full-size short-bed trucks with a gooseneck hitch fitted
✗ No, UWS recommends a 75-gallon tank instead
Compact and mid-size trucks (Tacoma, Ranger, Colorado, Frontier)
✗ No, UWS states this tank will not fit
Flatbeds, trailers and stationary use
✓ Yes, on a flat surface rated for the loaded weight
Fit guidance: UWS states this hammerhead tank fits all full-size trucks and will not fit compact or mid-size trucks, and that it will not fit a short-bed truck with a gooseneck hitch installed (UWS recommends a 75-gallon tank for that case). Verify fitment against the published dimensions: 59" long, 31" wide, 24.75" tall, and allow another 2-3/4" of height for the fill cap. Filled with diesel this tank carries about 710 lb of fuel on top of its 150 lb empty weight, so confirm your truck's payload rating before ordering. This is a spec-fit product with no vehicle-specific mounting kit; mounting hardware is not included.
Specifications
UWS Part Number: TT-100HH-CB
Tank Capacity: 100 gallons
Tank Style: Combo Hammerhead
Material: Aluminum alloy
Wall Thickness: .125"
Finish: Bright Aluminum
Overall Length: 59"
Overall Width: 31"
Overall Height: 24.75"
Upper Section Height: 13"
Lower Tub Width: 18"
Tub Length: 48"
Tub Width: 13"
Tub Height: 9.75"
Tool Box Storage Volume: 6.5ft³
Tool Box Material: .125" aluminum alloy
Tool Box Lid: Single Lid, patented RigidCore foam-filled
Tool Box Latch: Paddle Handle, stainless steel, connecting rod both sides
Tool Box Weather Seal: MicroSeal gasket
Internal Baffles: Yes
Fill Cap: Lockable commercial-grade vented cap with reinforced collar (padlock not included)
Drain Plug: 3/8", set nearly flush with the tank floor
Pressure Test: 100% pressure-tested
Mounting: Commercial-grade mounting flanges (mounting hardware not included)
DOT Rating: DOT-compliant for transporting Class 3 combustible fuels only, such as diesel
Keys Supplied: 2, for the tool box lock handles
Intended Use: Private use only; UWS states the tank is not intended for commercial use and does not meet 49 CFR 393.65 or 393.67
Not Compatible With: Gasoline and other flammable fuels, diesel exhaust fluid (DEF), and other corrosive materials
Type: Set the tank into the bed and bolt it down through the mounting flanges · Time: About 1 hour with a second person or a hoist · Tools: Drill and a 3/8" drill bit, ratchet and socket set, tape measure and a marker, plus a hoist or a second person to lift the tank · Difficulty: Easy, and UWS rates the installation difficulty as Easy
Empty the tank completely before you ever move it; UWS states it should be lifted only when empty. Before you drill into the bed, look underneath and confirm the bit cannot reach a brake or fuel line, wiring or the fuel tank, and keep fasteners far enough from the fuel tank that a collision cannot drive one into it. The tank must finish up securely bolted to the bed. Mounting hardware is not supplied, so match the fastener size to your bed and use backing plates or large washers underneath; UWS's general torque guidance is 16 ft-lb for a 3/8" bolt and 28 ft-lb for a 1/2" bolt, but if your hardware comes with its own figures, use those. The tank must stay vented at all times, must not be pressurized, and UWS requires an automatic shutoff nozzle and a fuel filter, none of which are supplied. Read the UWS installation manual through before you start, and check your state and local rules on transporting fuel before the first fill.
Resources
Everything you need for your UWS 100-Gallon Hammerhead Combo Aluminum Transfer Tank with 6.5ft³ Tool Box, Bright Aluminum, in one place.
Warranty. Limited lifetime warranty from UWS on the tank, with one year on the finish and one year on parts. Damage from overloading, improper installation, or hauling a liquid outside the tank's rating is not covered.
Free shipping. This item ships free to the lower 48 states. Because it is an oversized item, it ships by freight and typically arrives in 3 to 7 business days.
Inspect on delivery. Please inspect the packaging before signing. If you see any damage, note it on the delivery receipt and contact us right away, and we will make it right.
Compliance. DOT-compliant for transporting Class 3 combustible fuels only, such as diesel. UWS states this tank is NOT approved for transporting flammable fuels such as gasoline, must never be connected to a vehicle's fuel system or used as an auxiliary fuel tank, and is not compatible with diesel exhaust fluid (DEF) or other corrosive materials. UWS also states the tank is for private use only, is not intended to be used commercially, and does not meet 49 CFR 393.65 and 393.67.
About UWS
UWS, United Welding Services, builds truck tool boxes and liquid transfer tanks and is part of the CURT Group family of towing and truck accessory brands under Lippert. The company is best known for two things it engineered rather than bought in: the patented RigidCore lid, which sandwiches solid foam between two metal plates so a tool box lid does not flex, bind or warp under load, and the MicroSeal gasket that keeps water, dust and road grime out of the box. Those details show up across the whole catalog, from a crossover box to a 100-gallon combo tank.
UWS aluminum transfer tanks are built for the same job the tool boxes are: living in a work truck bed and being useful on the worst day of the week. Every tank is welded from heavy-duty .125" aluminum alloy, fitted with internal baffles so the load does not surge when you brake or corner, given a lockable commercial-grade vented fill cap and a near-flush drain plug, and 100% pressure-tested before it ships. UWS states these tanks are designed, fabricated and welded in Florida.
Prestige Truck is an authorized UWS dealer. Everything we ship is new, covered by the full UWS factory warranty, and backed by UWS's own service and parts support.
Compare The Range
How this compares to similar models
The closest alternatives side by side, so you do not have to keep tabs open.
Model
This OneUWS 100-Gallon Hammerhead Combo Aluminum Transfer Tank with 6.5ft³ Tool Box, Bright Aluminum (TT-100HH-CB)
Tool Box Vs. Mud Vs. Pressure Washer | MicroSeal Weather Test
UWS buries a tool box in mud and then takes a pressure washer to it, to show what the MicroSeal gasket on this combo's lid is actually doing.
Worth watching if the box is going to live in an open bed through a winter of road salt and spray.
UWS Hammerhead Transfer Tanks
Dean from CURT Group, the UWS parent brand at the time, presents the hammerhead tank line this tank comes from. The point of the shape is the narrowed base: it drops between the wheel wells, which is how one 100-gallon tank covers virtually every full-size pickup on the road, short beds included.
He also covers the L-shape and the combo configuration with an integrated tool box, and the full-aluminum and steel-aluminum builds UWS offers. All UWS transfer tanks are 100 percent pressure tested for safety before shipping.
Tool Box Vs. Pickup Truck | RigidCore Strength Test
UWS drives a pickup truck onto one of its tool box lids. The point is the patented RigidCore construction used on this combo's lid: two metal plates with solid foam between them, which is what stops a lid flexing, binding or warping under load.
If you have ever had a tool box lid you could not close properly after someone stood on it, this is the two minutes that explain the difference.
Frequently Asked Questions
Straight answers on specs, fit and support
What can I legally haul in this tank, and what can I not?
Diesel is the intended use. UWS rates the tank DOT-compliant for transporting Class 3 combustible fuels only, such as diesel, and for non-flammable liquids including water. The exclusions are explicit in UWS's own installation manual and worth reading before you buy: it is NOT approved for flammable fuels such as gasoline; it must never be connected to your truck's fuel system or used as an auxiliary tank; and it is not compatible with diesel exhaust fluid or other corrosive materials, so DEF is out. UWS also states the tank is for private use only, is not intended for commercial use, and does not meet 49 CFR 393.65 or 393.67, which are the federal fuel-system rules for commercial motor vehicles. If you run under a DOT number, check that against your own compliance requirements before ordering.
Will it fit my truck bed?
UWS states this hammerhead tank fits all full-size trucks and will not fit compact or mid-size trucks. The narrowed base drops between the wheel wells. It will not clear a gooseneck hitch in a short bed, and UWS recommends a 75-gallon tank in that case. The tank is 59" x 31" x 24.75", plus about 2-3/4" for the fill cap.
How much does it weigh when it is full?
The tank is 150 lb empty. Diesel runs about 7.1 lb per gallon, so a full 100 gallons adds roughly 710 lb, for about 860 lb sitting in the bed before any other cargo. That is more than a half-ton truck's remaining payload in many configurations, so check the door-jamb sticker rather than assuming. Always drain the tank completely before relocating it.
What exactly comes in the crate?
UWS's installation manual lists the carton contents as the tank, two keys, the filler neck and cap, and a 3/8" drain plug. The keys are for the tool box lock handles and UWS supplies them with combo models only, which includes this one. Mounting hardware is not included and UWS is explicit that you must buy your own to suit your bed. You will also need an automatic shutoff nozzle, which UWS requires and does not provide, and a fuel filter. There is no pump, hose or padlock in the crate.
How much will the tool box actually hold?
The tool box gives you 6.5ft³ of storage, and because it is built into the tank it does not cost you any additional bed floor. It uses the patented RigidCore foam-filled lid, a MicroSeal gasket to keep weather out, and stainless steel paddle handles linked by a connecting rod so you can open it from either side of the truck.
How does it ship, and what is the warranty?
This is a freight item, not a parcel item. At about 154 lb it moves by LTL freight, so expect a delivery appointment and plan how you will get it off the truck: a forklift, a loading dock or several people. UWS covers the tank with a limited lifetime warranty, with one year on the finish and one year on parts.
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