GMC Sierra HD & Chevy Silverado HD Skid Plate Buyer's Guide (2500HD / 3500HD).

A 2500HD or 3500HD weighs the better part of four tons, and the heaviest, most expensive parts of it hang in the open under the frame. The factory tucks the engine oil pan, transmission, and transfer case low and largely unguarded — fine for a paved jobsite, a real liability on a forest road, a rutted ranch two-track, or anywhere you'd point an AT4X or a ZR2 HD. One unseen rock or stump strike can crack a pan or split a transfer-case housing, and on a diesel that's a five-figure bad day.

This guide covers what's exposed under the current-generation Sierra HD and Silverado HD, where the factory protection stops, how coverage breaks down by trim and engine, and the six things to check before you buy a skid plate. We sell 1/4" aluminum armor for these trucks now — so we'll also lay out exactly what Juggernaut's coverage includes and answer the questions HD owners actually ask.

Jump to: what's exposed · the factory coverage gap · fitment by trim & engine · how to choose · Juggernaut spec · the install · FAQ

What's exposed under an HD

The General Motors HD platform — GMC Sierra 2500HD/3500HD and Chevrolet Silverado 2500HD/3500HD — shares a frame and driveline layout, so the vulnerable hardware sits in roughly the same places on both. Three zones matter most:

• Engine / oil pan. Whether you've got the 6.6L Duramax turbodiesel or the 6.6L gas V8, the oil pan is the lowest casting up front and the first thing to meet a high-centering rock.
• Transmission. The Allison (diesel) or the gas automatic sits just aft of the engine, low in the tunnel, with the pan and valve body exposed to debris kicked up or struck from below.
• Transfer case. On 4WD trucks the transfer case is one of the lowest-hanging and most fragile cast housings underbody — a direct hit can crack the case and dump fluid.

The pattern across the underbody is the same: heavy, costly, hard-to-replace components with thin or no factory shielding between them and the trail.

The factory / OEM coverage gap

Off-road HD trims — the GMC AT4 and AT4X, the Chevy Z71, and the genuinely trail-capable Silverado ZR2 HD — do come with more underbody attention than a base work truck, and GM has built increasingly serious off-road HDs in this generation. But "more than a base truck" is a low bar. Factory skid plates are typically stamped steel or composite, concentrated up front, and engineered to protect against light debris and forward impacts — not the full-length, repeated, low-speed rock contact that real off-road use delivers. Behind the front shield, the transmission and transfer case are usually left to fend for themselves.

Base and work-truck HDs get even less. So the real-world gap on almost every HD is the same: front-biased factory protection, with the driveline behind it largely open. Aftermarket armor closes that gap — but quality 1/4" aluminum coverage for these trucks is scarce, because most makers chase the higher-volume half-ton and mid-size platforms first. That's why we built HD coverage.

Fitment by trim & engine

Current-generation Sierra HD and Silverado HD run 2020 to present, with a notable refresh arriving for the 2024+ model years. Because Sierra and Silverado HD share the platform, fitment is closely related across the two — but cab, bed length, engine, and trim all change what hangs where. A few things to confirm before you order:

• Engine. The 6.6L Duramax diesel and 6.6L gas V8 package the front end differently. Make sure any engine/oil-pan plate is called out for your specific engine.
• Drivetrain. 4WD trucks have a transfer case to protect; 2WD trucks don't. Confirm which transfer-case coverage (if any) applies to your configuration.
• Trim. Off-road trims like AT4X and ZR2 HD can carry different factory front hardware, ride height, or front fascia than a standard SLE/LT, which can affect how front coverage indexes.
• Model year. The 2024+ refresh changed front-end styling and interior details — but our plates mount to points that carried through the refresh, so one plate covers 2020–2026.

The honest version: don't assume. Tell us your year, trim, engine, and 2WD/4WD and we'll confirm exactly which plates fit before you spend a dollar. If you want to compare materials first, here's our breakdown of aluminum vs. steel.

How to choose: a 6-point checklist

Skid plates are not all the same, and the spec sheet is where the differences live. Run any HD skid plate — ours or anyone's — through these six points:

1. Coverage. Front-skid-only protects the oil pan and not much else. Look for a system that armors the full run of the driveline — engine/oil pan, transmission, and transfer case (on 4WD) — not just the nose.
2. Thickness. A lot of "heavy-duty" plate is 3/16" (0.188"). Juggernaut runs 1/4" (0.250") — meaningfully thicker, and thickness is what resists deformation on a hard hit.
3. Alloy. "Aluminum" is not a spec. The grade and temper are. We use 5052-H32 marine-grade aluminum, chosen for its strength, corrosion resistance, and how it takes a press-brake fold without cracking.
4. Finish. Plenty of plates ship bare and start oxidizing the first wet drive. Ours are powder-coated black as standard — corrosion protection and a finished look, not a paid upgrade.
5. Serviceability. You still have to change oil and service the driveline. Good armor accounts for drain and service access so you're not pulling the whole plate for routine maintenance.
6. Warranty. Some armor carries a 1-year warranty. Juggernaut backs its plates with a lifetime warranty — the difference between a part the maker stands behind for good and one that's on the clock.

The Juggernaut spec

Here's what every Sierra HD and Silverado HD plate we make is built to:

Browse current HD coverage in the Sierra HD & Silverado HD skid plate collection — or go straight to the Chevy Silverado HD skid plate package or the GMC Sierra HD skid plate package. Available plates cover the engine/oil pan, the transmission with a catalytic-converter shield, and the transfer case — confirm your fitment for the exact mix that fits your truck.

The install

Every HD plate is a true bolt-on — no drilling, no cutting, mounting to existing frame points with the hardware included. Watch the full install video or follow the written step-by-step instructions. In the Denver area? Our Wheat Ridge shop will do it for you.

Frequently asked questions

Will these fit both my GMC Sierra HD and a friend's Chevy Silverado HD?
The Sierra HD and Silverado HD share the same platform, so fitment is closely related — but trim, engine, drivetrain, and model-year details can differ. Confirm year/trim/engine for each truck and we'll match the right plates.

Do these fit the diesel and the gas V8?
We make coverage for both the 6.6L Duramax and the 6.6L gas V8 — one engine/oil-pan plate covers the 2020+ HD platform. Tell us your year, engine, and configuration when you order and we'll confirm the fit before it ships.

Will a skid plate fit my AT4X or ZR2 HD?
Off-road trims are exactly who this armor is for. Those trucks can carry different factory front hardware and ride height, so confirm your specific trim and model year so we get the front coverage right.

Do you make a fuel tank skid plate for the HD trucks?
Not yet — our HD line currently covers the engine/oil pan, transmission + cats, and transfer case. If you'd want tank coverage for your HD, call or text and tell us — demand is how new plates get made here.

Is 1/4" aluminum strong enough, or should I run steel?
1/4" 5052-H32 aluminum gives you serious impact resistance at a fraction of the weight of comparable steel — meaning less mass hanging off the frame and no rust. We break down the full trade-off in our aluminum vs. steel guide.

Do I have to drill into my truck?
No. Our HD plates are bolt-on with no drilling — they use existing mounting points so the install is reversible and clean.

Can I still change my oil with the plates on?
Yes. We design for service access so routine maintenance doesn't mean removing your armor. If you'd rather not get under the truck, our Wheat Ridge shop installs.

Can you install them for me?
We can. We run a full 4x4 install shop at 4840 Van Gordon St Unit #300 in Wheat Ridge, Colorado. Call or text (970) 341-4221 to book.

Cover the whole driveline

If you take a Sierra HD or Silverado HD anywhere the pavement ends, front-only factory protection isn't enough — the transmission and transfer case need armor too. Juggernaut builds that full driveline coverage in 1/4" 5052-H32 aluminum, powder-coated black, bolt-on, and backed for life. Tell us your year, trim, and engine and we'll confirm the exact plates that fit. Email sales@juggernautusa.com, call or text (970) 341-4221, or shop the Sierra HD & Silverado HD collection.

Sources

• MatWeb — Aluminum 5052-H32 property datasheet
• AZoM — ASTM A36 mild/low-carbon steel properties