Commercial Truck Classes 1–8, Explained

How the classes work

Commercial trucks are grouped into eight classes by GVWR — gross vehicle weight rating, the maximum loaded weight the manufacturer rates the vehicle for. It's a rating, not a measurement: an empty Class 8 tractor is still Class 8. You'll find the number on the sticker in the driver's door jamb.

Light duty — Classes 1, 2 and 3

• Class 1 — up to 6,000 lb. Small pickups, SUVs, most vans.
• Class 2 — 6,001 to 10,000 lb. Half-ton and three-quarter-ton pickups; Sprinter and cargo vans sit here.
• Class 3 — 10,001 to 14,000 lb. One-tons: F-350, Ram 3500, Silverado 3500.

This is where most diesel pickups live, and it's the bulk of our light-duty work — Power Stroke, Cummins, and Duramax, plus Sprinter vans and import diesels. No CDL required.

Medium duty — Classes 4, 5 and 6

• Class 4 — 14,001 to 16,000 lb. F-450, small box trucks.
• Class 5 — 16,001 to 19,500 lb. F-550, larger service bodies.
• Class 6 — 19,501 to 26,000 lb. Standard box and delivery trucks, single-axle vocational.

This is delivery-fleet country, and the class where emissions problems concentrate — short routes never build the exhaust heat a DPF needs. It's the world of Isuzu N-Series, Hino, and Freightliner M2. See medium-duty diesel service and DPF cleaning.

Heavy duty — Classes 7 and 8

• Class 7 — 26,001 to 33,000 lb. City tractors, refuse trucks, larger vocational chassis.
• Class 8 — 33,001 lb and above. Semi tractors, dump trucks, mixers, heavy vocational.

Air brakes, heavy alignment, and annual DOT inspections define the service picture here — Peterbilt, Kenworth, Freightliner, Volvo, Mack, and International. See heavy-duty parts & repair.

The CDL line sits at 26,001 lb. A commercial driver license is generally required at 26,001 lb GVWR or gross combination weight rating — so Class 7 and 8 are CDL territory, along with many Class 6 combinations pulling a trailer. That threshold is why our concierge pickup sends a CDL-licensed driver when the vehicle requires one, and a regular licensed driver when it doesn't.

Class matters less than duty cycle

The most common maintenance mistake we see is treating class as the schedule. A Class 6 delivery truck doing forty stops a day usually needs a shorter interval than a Class 8 tractor running steady highway miles — despite weighing half as much — because stop-and-go work is harder on oil and emissions systems than sustained running. That's why we set PM intervals per vehicle from how it's actually used rather than from a number on a sticker.

What doesn't fit the class system

Plenty of what we work on isn't classified at all — trailers are rated separately by GVWR and axle capacity, and off-road equipment like skid steers and excavators sits outside the system entirely. See truck & trailer repair, livestock and gooseneck trailers, and heavy equipment.

Not sure what you've got?

Call 512-717-2777 with the year, make, and model — or the VIN — and we'll tell you the class and what it needs. We service Classes 2 through 8 plus trailers and equipment from 2900 N FM 973, Austin, TX 78725, across the Greater Austin Area (Travis, Bastrop, Williamson, Hays).

Common questions

What are the commercial truck classes?

Trucks are grouped 1 through 8 by GVWR — gross vehicle weight rating, the maximum loaded weight the manufacturer rates the vehicle for. Classes 1 to 2 are light duty up to 10,000 lb, Class 3 to 6 is medium duty from 10,001 to 26,000 lb, Class 7 is 26,001 to 33,000 lb, and Class 8 is anything above 33,000 lb. The class is set by the rating on the door jamb sticker, not by how much the truck happens to be carrying.

What class is my truck?

Check the sticker in the driver door jamb for GVWR and match it to the bands: a half-ton pickup is Class 2, a one-ton like an F-350 or Ram 3500 is Class 3, a typical box or delivery truck is Class 5 to 7, and a semi tractor is Class 8. If the sticker is missing or unreadable, the VIN will tell you — bring it in and we can look it up.

What truck classes does Modern Diesel service?

Classes 2 through 8, plus trailers and off-road diesel equipment. That covers diesel pickups and one-tons, box and delivery trucks, vocational and medium-duty chassis, and Class 8 tractors — along with the Sprinter vans, import diesels, skid steers, and excavators that do not fit the class system at all.

At what weight do you need a CDL?

Generally a commercial driver license is required at 26,001 lb GVWR or gross combination weight rating, which puts Class 7 and Class 8 in CDL territory along with many Class 6 combinations. That threshold is why our concierge pickup sends a driver who is CDL-licensed when the vehicle requires one, and a regular licensed driver when it does not.

Does truck class change how often it needs service?

Class matters less than duty cycle. A Class 6 delivery truck doing short city routes usually needs a shorter service interval than a Class 8 tractor running steady highway miles, despite weighing half as much — because stop-and-go work is harder on oil and emissions systems than sustained running. We set maintenance intervals per vehicle from how it is actually used rather than from its class alone.