Commercial trucks · Elgin CDJR
What Is a Cab Chassis?
A cab chassis (or chassis cab) is a truck that leaves the factory with a cab and a bare frame behind it instead of a pickup bed. A body builder then fits whatever the job needs: a dump body, a service body, a flatbed, a crane or a box. Here is how the Ram 3500, 4500 and 5500 Chassis Cab line is rated and how to spec one.
Quick answer
A cab chassis is a truck sold as a cab and frame with no bed, built so a third-party upfitter can mount a work body before delivery. Ram sells three: the 3500 Chassis Cab (Class 3, with a 10,000-lb GVWR Class 2 version), the 4500 (Class 4) and the 5500 (Class 5), in Regular and Crew cab, 4x2 and 4x4, with cab-to-axle lengths of 60, 84, 108 and 120 inches to match the body. Engines are a 6.4-liter HEMI V-8 (375 hp, 429 lb-ft) or the 6.7-liter Cummins high-output turbo diesel (360 hp, 800 lb-ft), both with an eight-speed automatic. With the Cummins the 5500 tows up to 34,380 lb and carries up to 11,530 lb of payload, at a 43,000-lb gross combined rating. The frame is clear above the rear rails, with through-the-frame wiring, PTO provisions and an available 2.4-kW inverter so bodies bolt on without cutting.
Cab chassis versus a pickup
Pickup
Comes with a bed. Fine for hauling in the bed and towing, but the bed is the body and cannot be changed without removing it.
Cab chassis
No bed; a flat frame with the fuel tank, exhaust and wiring kept below the top of the rails. The body is chosen for the job and mounted by an upfitter, which is why fleets buy them.
Why the ratings differ
Chassis cabs are rated by GVWR class (3, 4 or 5) because the finished weight depends on the body. The 4500 and 5500 use heavier axles, brakes and frames than any pickup.
Ram Chassis Cab lineup
| Model | Class | Engine | Max towing | Max payload | GCWR |
|---|---|---|---|---|---|
| Ram 3500 Chassis Cab | Class 3 (plus a 10,000-lb GVWR Class 2 version) | 6.7L Cummins HO diesel | 25,680 lb | 6,830 lb | 33,000 lb |
| 6.4L HEMI V-8 | 18,880 lb | 7,710 lb | 25,000 lb | ||
| Ram 4500 Chassis Cab | Class 4 | 6.7L Cummins HO diesel | 29,440 lb | 8,560 lb | 37,500 lb |
| 6.4L HEMI V-8 | 21,240 lb | 9,390 lb | 28,500 lb | ||
| Ram 5500 Chassis Cab | Class 5 | 6.7L Cummins HO diesel | 34,380 lb | 11,530 lb | 43,000 lb |
| 6.4L HEMI V-8 | 21,230 lb | 12,370 lb | 28,500 lb |
Payload here is the chassis rating before a body is fitted; the body's weight comes out of it. Trims are Tradesman, SLT, Laramie and Limited.
Built for upfitting
- Nothing above the rear frame rails: fuel, exhaust, DEF and wiring stay below the top of the frame so flat bodies mount directly.
- Four cab-to-axle lengths (60, 84, 108 and 120 inches) so the body sits on the axle correctly; the upfitter specifies which one.
- Through-the-frame plumbing and electrical, a Vehicle System Interface Module for body controls, and PTO provisions for left- or right-side operation.
- Dual alternators up to 480 amps and an available 2.4-kW onboard inverter that can be relocated for the body.
- Up to 74 gallons of fuel in dual tanks; the DEF filler is at the rear of the cab on the driver's side.
- Heavy-duty snow plow prep standard on the 3500, available on 4500 and 5500; electronic front-axle disconnect available on 4x4 models.
- Adaptive cruise control and forward-collision warning standard, with an available 12-inch Uconnect 5 screen.
Common bodies
| Body | Typical use | Usual chassis |
|---|---|---|
| Service or utility body | Trades: compartments for tools and parts, often with a crane | 3500, 4500 |
| Dump body | Landscaping, snow and ice, construction materials | 3500 to 5500 |
| Flatbed or stake body | Hay, equipment, building supplies; fits the widest range of loads | 3500 to 5500 |
| Box or van body | Deliveries, moving, mobile workshops | 4500, 5500 with 108 or 120-in. CA |
| Crane or mechanic's body | Field service, tire service, heavy parts | 4500, 5500 |
| Specialty: ambulance, tow and recovery, bucket | Emergency, towing, utilities | 4500, 5500 |
How ordering works
- Tell us the body you need and the heaviest load you will carry or tow; that sets the class and the cab-to-axle length.
- Choose cab, drive and engine. Diesel for towing and long hours at load; the HEMI for lower purchase cost and shorter duty cycles.
- We order the chassis with the right prep packages (PTO, upfitter switches, snow plow prep, inverter).
- The chassis ships to the body builder you choose or one we work with; Ram's Body Builder's Guide gives them the mounting and electrical specs.
- Delivery and registration are handled as one vehicle, and commercial financing can cover the chassis and body together.
Frequently asked questions
What is the difference between a cab chassis and a pickup truck?
A pickup comes with a bed. A cab chassis is sold as a cab and bare frame so an upfitter can mount a work body such as a dump, service, flatbed or box body.
What is a chassis cab used for?
Any job that needs a specific body: landscaping and snow removal, construction, trades, deliveries, utilities, towing, ambulances and fire apparatus.
How much can a Ram 5500 Chassis Cab tow?
Up to 34,380 lb with the 6.7-liter Cummins high-output diesel, at a gross combined weight rating of 43,000 lb (Ram, 2026).
What engines are in the Ram Chassis Cab?
A 6.4-liter HEMI V-8 (375 hp, 429 lb-ft) or the 6.7-liter Cummins high-output turbo diesel (360 hp, 800 lb-ft), each with an eight-speed automatic.
Can I buy a cab chassis with the body already on it?
Yes. We can order the chassis and arrange the upfit so the finished truck is delivered ready to work, financed as one vehicle.
Spec a work truck
Our commercial team in Streamwood orders Ram Chassis Cabs with the right prep packages and coordinates the body. Bring the job; we will match the truck to it.
Sources
Ratings are Ram's for the 2026 Chassis Cab, checked against Stellantis press material on October 20, 2026. Ratings vary with configuration; the body builder's final weights govern. Prices are not quoted here.
- 2026 Ram Chassis Cab press kit (May 1, 2026), Stellantis North America media (Canada)
- Press Kit: 2024 Ram Chassis Cab (Sept. 7, 2023), Stellantis North America media