How to Pick the Right Semi-Truck Storage Box from Merritt
Tool boxes handle wrenches and straps, but today’s tractors carry far more—DEF jugs, PPE, chains, log books, even coolant. When you need purpose-built compartments that tuck into odd frame spaces …
Tool boxes handle wrenches and straps, but today’s tractors carry far more—DEF jugs, PPE, chains, log books, even coolant. When you need purpose-built compartments that tuck into odd frame spaces or double as steps, Merritt’s aluminum semi-truck storage box lineup delivers. Use the guide below to match each box style to the problem it solves so you can reclaim dead space, cut cab clutter, and keep gear protected from weather and theft.
| Storage-box family | Where it mounts | What it’s best at | Typical capacities |
|---|---|---|---|
| Between-the-Frame Box | Hangs in the frame rails between cross-members | Adds enclosed space without widening the truck profile; perfect when tanks or fairings crowd the rails | Small tools, gloves, spill kit, triangles |
| Side Fairing Box | Slides between aero fairing panel & frame | Uses a spot most fleets overlook; top-opening lid for rapid access | Fluids, PPE, small parts bins |
| Peterbilt-Style Cab-Access Boxes (Side & Full) | Bolts to cab entry; step or no-step versions | Combines driver step and secure storage; extruded door frame keeps wash-bay water out | Chains, binders, aerosol cans, pry bars |
| Off-Highway Box | Cross-frame mount behind cab | Tall, sloped, diamond-plate lid shrugs off mud and bark; quick top access | Longer chain binders, tarps, hydraulic caps |
| DEF Storage Box | Frame-rail or deck mount | Purpose-sized for 1-gal or 2.5-gal DEF jugs; keeps fluid clean, cool, and locked | Four 1-gal or two 2.5-gal jugs |
| Buddy (Side) Box | Small cab-side companion to larger saddle box | Narrow profile for day-cab frames; great add-on when primary box is full | Small tools, gloves, personal items |
1. Squeeze Storage Inside the Rails
Between-the-Frame Boxes reclaim the empty void most trucks leave untouched. Drop the box between cross-members with a supplied clamp kit—no new holes—and you’ve got a weather-sealed compartment that doesn’t interfere with tanks, fairings, or tire spray. Ideal for fleets that run wide fuel barrels or need lift-axle clearance.
Quick spec tips
- Verify fore-aft clearance to driveline carrier bearing.
- Choose bright or diamond-plate lid to match visible gear.
2. Turn Aero Fairings into Useful Real Estate
Side fairings save fuel but hide frame-space you could be using. Merritt’s Side Fairing Box slides between fairing panel and frame, top-hinges open for stand-up access, and seals tight with an automotive-grade gasket. Fleet bonus: door sits behind the fairing’s aerodynamic plane, so MPG gains stay intact.
3. Combine Safe Steps & Secure Storage
The Peterbilt-Style Cab-Access Box family gives drivers a knurled, drain-through step plate plus an aluminum enclosure strong enough for chain binders or ratchets. Choose the compact Side model for tight day-cabs, or the deeper Full version when you want maximum capacity on sleepers.
4. Dominate Harsh Off-Road Jobs
Logging roads and construction sites punish hinged lids. Off-Highway Boxes use a sloped, diamond-plate top that sheds mud and deflects debris. Cross-frame mounting centers the weight and clears side-frame loaders or stake racks. Pair with folding handles for crane-lift convenience.
5. Keep DEF Secure & Temperature-Stable
SCR engines need clean DEF—contaminated fluid triggers derates. The dedicated DEF Storage Box holds four 1-gal or two 2.5-gal jugs in an aluminum body that dissipates heat better than steel or plastic. Optional front louvers promote airflow; internal brackets stop jug bounce on washboard roads.
How to Choose Your Semi-Truck Storage Box in 4 Steps
- Identify dead space – Between rails, behind fairing, cab step, or cross-frame.
- List items to store – Fluids? Long chains? Personal PPE?
- Match capacity & door style – Top-open for fast drop-in loads; front-swing for tall gear.
- Select mounting kit – Merritt offers frame-drill and no-drill clamps to match box length and weight.
Why Merritt Storage Boxes Win
- All-aluminum construction – Up to 40 lb lighter than steel, no rust bleed.
- Lap-joint welded corners – Stronger, more water-tight than riveted imports.
- Automotive seals & bullet hinges – Long life in freeze–thaw cycles.
- 10-day custom lead time – Need an odd depth or special shelf? We cut and weld in-house.
Ready to convert wasted frame space into productive, weather-proof storage?
Browse every Merritt storage box ➜
https://merrittproducts.com/product-category/heavy-duty/storage-boxes/
Talk fitment with our team: 800-525-0107 | alum.products@merrittproducts.com
Choose the semi-truck storage box built for your route—not just your toolbox.
