The UWS 48" underbody tool box hangs below the deck of a flatbed, dump body or trailer, which is where storage belongs on a truck whose deck has to stay clear for work. It is 48" long, 19" deep and 18" tall, holding 9.2ft³ behind a lockable folding T-handle. The door drops down on stainless steel cables so the whole opening is in front of you at waist height. The tub is one-piece 0.058" aluminum, so there is no seam along the floor and nothing to rust when the finish gets chipped by road debris, and the MicroSeal gasket keeps spray and grit out of a box that lives directly in the weather. Finished in bright aluminum. Two keys are in the carton; mounting brackets and hardware are not included.
What's Included:
UWS 48" underbody truck tool box
2 keys
UWS Underbody Tool Boxes
UWS's film on the underbody line: boxes that hang below the deck of a flatbed, dump body or trailer so the deck itself stays clear for work. It covers the MicroSeal gasket that shuts dust and water out and the stainless steel cables that let the door drop a full 90 degrees, putting the whole opening in front of you at waist height.
One thing to note before you watch. The boxes on camera are the 14-gauge steel version of this line. This listing is the aluminum underbody box, which uses the same mounting position, the same door and cable arrangement and the same MicroSeal seal, in a one-piece 0.058" aluminum tub.
Features
9.2ft³ of Storage That Costs You No Deck Space At 48" x 19" x 18" the box mounts under the deck, so the flatbed, dump body or trailer floor above it stays completely clear. On a working truck that is storage you get for free.
Single-Door on Stainless Steel Cables The door drops down and is caught by stainless steel cables that take the weight and hold the opening steady while you work. Stainless matters here: this is the one box on the truck that gets sprayed with salt water every winter.
One-Piece 0.058" Aluminum Tub Extra-thick aluminum formed from a single sheet, so there is no welded seam along the floor of the box for water to find. Aluminum also will not rust where a stone chips the finish, which happens constantly in this mounting position.
Lockable Folding T-Handle Keyed for security and it folds flat when it is not in use, so it does not stand proud of the box where a loading dock or a curb can catch it. One hand opens it.
MicroSeal Gasket A full-perimeter gasket seals the door against the constant road spray this box lives in. It is a cataloged UWS service part, so it can be renewed rather than lived with.
Designed, Fabricated and Welded in Florida UWS builds this box in its own Florida plant and backs it with a limited lifetime warranty on workmanship and materials, one year on the finish and one year on parts.
Fitment & Compatibility
Application
Fit
Flatbeds and stake beds
✓ Yes, the intended application
Dump bodies
✓ Yes, mounted clear of the hoist and the tailgate swing
Utility and equipment trailers
✓ Yes, where the frame can carry the load
Service bodies with factory compartments
● Usually redundant, the body already has boxes
Standard pickup with a factory bed
✗ No, there is no usable frame rail space under a pickup bed for this box
Fit guidance: This is a universal-fit box, so what decides the fit is the frame, not the year and model. You need 48" of clear run along the frame, 19" of depth and 18" of height between the underside of the deck and your minimum ground clearance. Mount it clear of the wheels, the suspension travel, the fuel tank, the exhaust and anything that swings, and remember a dump body's hoist needs room. Brackets and hardware are not included and must be at least 1/4" steel with the underside of the box supported. If you are not certain about the frame, UWS recommends having a truck up-fitter do the mounting.
Specifications
Model: 48" Underbody Truck Tool Box
UWS Part Number: TBUB-48
Type: Underbody box, mounts below a flatbed, dump body or trailer deck
Type: Bolted or welded to the frame or body of a flatbed, dump body or trailer using brackets rated for the load · Time: About 1 to 2 hours, longer if brackets have to be fabricated · Tools: Drill and bit set, ratchet and socket set, tape measure, level; a welder if you are welding the brackets · Difficulty: Moderate. UWS recommends a truck up-fitter or equipment dealer for the mounting
Read this before you order: no mounting brackets and no hardware come with the box, and UWS is specific about what the mount has to be. Brackets should be equal to or thicker than 1/4" steel, and the underside of the box must be supported rather than left hanging. UWS sells matching 18" x 18" L-brackets separately (part TBUB-1818-LB) for boxes of this depth and height. Check under the deck for brake lines, fuel lines, wiring and the fuel tank before you drill anything. UWS is explicit that a tool box is not a place for flammables or hazardous material, so no fuel cans, solvents, propane or cutting torches. Never load past the vehicle manufacturer's rated capacity.
Resources
Everything you need for your UWS 48" Underbody Truck Tool Box, Single-Door Bright Aluminum, in one place.
Warranty. Limited Lifetime Warranty (One-Year Finish, One-Year Parts) from UWS, covering workmanship and materials. Normal wear, damage from overloading, and damage from improper installation are not covered. UWS stocks handles, locks, gas struts, gaskets, cables and keys as individual service parts.
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.
About UWS
UWS is short for United Welding Services, and the name is the point. The aluminum boxes in this line are designed, fabricated and welded in Florida rather than assembled from imported panels, and the tub is formed from one piece of extra-thick aluminum so there is no seam along the floor of the box for water to work its way into. UWS is part of the CURT Group, a Lippert company, which is what puts a national warranty and a real replacement-parts program behind a box that is still built in a single plant. Handles, gas struts, lid gaskets, striker brackets and keys are all cataloged parts you can buy years later, which is the practical difference between a box you repair and a box you replace.
An underbody box is the only kind of storage that costs a flatbed nothing at all, because it lives in the space between the deck and the road that was doing no work anyway. That position is also the harshest one on the truck: constant spray, salt, stones and vibration. Aluminum is the reason this box tolerates it. There is no steel to rust from a stone chip, and at 40.000 lb it adds far less to the payload than the equivalent steel box. UWS is specific about the mounting: brackets should be at least 1/4" steel and the underside of the box has to be supported, not left hanging on its flanges.
Prestige Truck is an authorized UWS dealer. Every box we ship is new and in the factory carton, covered by the full UWS factory warranty, and backed by the UWS replacement-parts program if a handle, strut, gasket or key ever needs renewing.
Frequently Asked Questions
Straight answers on specs, fit and support
Does it come with mounting brackets?
No. The carton holds the box and two keys only. UWS leaves brackets out because the mount depends entirely on the frame you are hanging it from. UWS sells matching 18" x 18" L-brackets separately as part TBUB-1818-LB, which suit a box of this 18" depth and 18" height.
What do the brackets need to be?
UWS specifies brackets equal to or thicker than 1/4" steel, and the underside of the box must be supported rather than left hanging off its top flanges. A box this size full of tools is a lot of weight bouncing on a frame, and the mount is what carries it.
Can I put this under a regular pickup bed?
Practically, no. An underbody box is designed for the open frame rails under a flatbed, dump body or trailer. A factory pickup bed does not leave the clear frame space this box needs. For a pickup, look at a UWS crossover, side or topside box instead.
How much does it hold, and how heavy is it?
9.2ft³ of storage, and the box itself weighs 40.000 lb empty. Aluminum is the point here: the equivalent steel box is significantly heavier, and on a truck that is payload you do not get back.
Will it survive being mounted down there?
That mounting position is the harshest on the truck, which is why the tub is one-piece aluminum rather than steel. Nothing rusts when a stone chips the finish, the door cables are stainless, and the MicroSeal gasket keeps the constant road spray out of the box.
What does the warranty cover?
A limited lifetime warranty on workmanship and materials, one year on the finish and one year on parts. Damage from overloading or from an inadequate mount is not covered, which is another reason to follow the 1/4" bracket specification.
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