Weather Guard 631 Underbed Truck Tool Box, 30 in Black Aluminum, 5.4 cu ft (631-5-02)

Blacked-out and light, the Weather Guard 631-5-02 is a 30" aluminum underbed box with a rugged gloss black look. Its welded diamond-plate body is 18" deep, holds 5.4ft³, and a gloss black ARMOR TUF finish hides grime while rust-proof aluminum shrugs off road salt on a flatbed, platform or dump body. A weathertight drop-down door keeps a service kit, tools and chains dry, the box stays light versus steel, and the 30" length leaves rail for a second box. Mounting hardware is not included, so you can match it to your frame.

What's Included:

• 631 Underbed aluminum diamond plate truck tool box, gloss black
• Drop-down door with stainless steel locking compression latch
• Three-point latching system with a drill-resistant lock core
• Two door support chains that hold the door as a work shelf
• Full-perimeter weather seal with rain gutter, pre-installed
• Weather Guard installation instructions
• Note: mounting brackets and hardware are not included, choose hardware to suit your frame or body

Features

Lightweight Aluminum Diamond Plate
The 631-5-02 is formed from welded aluminum diamond plate, so it adds locking underbody storage without the weight of steel. Aluminum naturally resists rust and corrosion, which matters for a box that lives down near the road spray and salt.

Black ARMOR TUF Diamond Plate
A gloss black ARMOR TUF powder coat covers the aluminum diamond plate to fight corrosion, chips and fading and give the box a blacked-out diamond-plate look. ARMOR TUF is Weather Guard's toughest coating, made to survive the salt, chemicals and weather an underbody box faces.

Weathertight Drop-Down Door
A full drop-down door drops open on two support chains that hold it level as a handy work shelf, then closes against a rain gutter and full-perimeter weather seal. Your tools stay dry and protected from road spray, dust and debris in the 5.4ft³ interior.

Stainless Locking Latch, Three-Point Latching
A stainless steel locking compression latch drives a three-point latching system with a drill-resistant lock core, so gear stays secure and the door pulls tight against the seal. The latch is easy to work even with gloves on.

Tool-Less QuickClip Door
The drop door adjusts from 90 to 180 degrees and pops off with QuickClips, no tools required, so you can drop it flat, use it as a loading shelf, or remove it entirely for full access and clip it back on in seconds.

Mounts Under the Deck, Frees Your Truck
The standard 18" deep body mounts on the frame rail below a flatbed, platform, service or dump body, so heavy tools and equipment ride secure and out of the way while your deck or bed stays open. It is the way to add locking storage to a truck with no usable bed floor. Mounting hardware is not included so you can match it to your frame.

Gloved-Hand D-Handle and a Wide Door Opening
The drop door on the 631-5-02 opens to a clear 13-1/2" high by 25-1/4" wide opening, so long tools and cases go in from the side of the deck instead of being lifted over a lip. Weather Guard fits a stainless steel D-handle that is easy to grip with gloves on and pulls the door tight against the seal, and the door itself drops level on its chains to work as a shelf.

Fitment & Compatibility

Specifications

• Series: 631 Series Underbed
• Style: Underbed frame-mount box, single drop-down door
• Storage Capacity: 5.4ft³
• Exterior Dimensions: 30"L x 18"W x 18"H
• Door Opening: 13-1/2" high x 25-1/4" wide
• Material: Welded aluminum diamond plate
• Finish: Gloss black ARMOR TUF powder coat
• Door: Single drop-down door, tool-less QuickClip hinges, 90 to 180 degrees, two support chains
• Latching: Stainless steel locking compression latch, three-point latching, drill-resistant lock core
• Weather Seal: Rain gutter with full-perimeter weather seal
• Mounting: Frame-rail mount below a flatbed, platform, service or dump body; mounting hardware not included
• Construction: Heavy Duty Welded
• Lid Construction: Heavy Duty C-Channel Reinforced
• Weather Strip Profile: Memory Resistant D-Shaped Ribbed
• Key Alike: Key Alike On Request
• Overall Size (Weather Guard published): 30-1/8"L x 18"W x 18"H
• Shipping Size: 30-3/4"L x 18-7/8"W x 18-1/2"H, 39 lb
• UPC: 783965042024
• Weight: About 42 lb (shipping)
• Warranty: Limited Lifetime
• Made In: USA

Installation

Type: Frame-rail mount below the deck, bolt-through (hardware not included)  ·  Time: About 1 to 2 hours  ·  Tools: Drill and bits, wrench or socket set, tape measure, marker, plus frame-appropriate mounting brackets and hardware (not included)  ·  Difficulty: Moderate, plan the mounting points and support the box while you bolt it up

Choose a clear spot on the frame rail below the deck with room for the door to drop open, then mount the box to the frame using brackets and hardware rated for the load (not included). Support the box while you fasten it, and seal any drilled holes with zinc-rich primer to prevent rust. Follow the Weather Guard Aluminum and Steel Underbed Boxes installation manual for hole layout and best practices. Because the box hangs below the deck, use hardware and brackets sized for the weight of the box plus its contents.

Resources

Everything you need for your Weather Guard 631 Underbed Truck Tool Box, 30" Black Aluminum, 5.4ft³, in one place.

• Official Weather Guard 631 Underbed Truck Tool Box, 30" Black Aluminum, 5.4ft³ installation manual (PDF), the manufacturer's step-by-step guide covering mounting, included hardware and torque specs.

Warranty, Shipping & Returns

Warranty. Limited Lifetime Warranty from Weather Guard against defects in materials and workmanship.

Freight shipping. This item is oversized, so it ships by freight to the lower 48 states and typically arrives in 3 to 7 business days. The freight cost is shown at checkout before you pay.

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. Mounting brackets and hardware are not included with this underbed box. Because the box mounts on the vehicle frame and carries load below the deck, use mounting hardware and brackets rated for the combined weight of the box and its contents, and confirm clearance so the drop-down door can open safely.

Returns. Unused items in their original packaging can be returned within 30 days of delivery. If an item arrives damaged, defective or wrong, return shipping is on us. See our Returns & Refunds Policy, or email support@prestigetruck.com with any question.

About Weather Guard

Weather Guard has built professional-grade truck and van storage in the USA for decades and is the storage brand tradespeople, contractors, and fleets reach for first. Its steel and aluminum tool boxes, ladder racks, and van-interior systems are engineered to survive daily jobsite abuse and keep expensive tools secure and organized.

Known for weather-tight seals, patented locking systems, and heavy-gauge construction, Weather Guard products mount cleanly on work trucks and vans and stand up to years of hard use. The lineup spans crossover, low-side, and saddle truck boxes, ladder and van racks, drawer units, and fuel and utility tanks, so an entire work vehicle can be outfitted from one brand.

Backed by a strong manufacturer warranty and US-based support, Weather Guard is the name pros trust to protect the tools their livelihood depends on.