Truck Models, Engines & Components Reference
Real specs on the current Class 8 trucks, engines, transmissions, axles, trailers, and major chassis parts you'll actually run into. Use it for research before a purchase, or just to settle a shop-talk argument.
Truck Models
The current Class 8 long-haul tractors. They make up the vast majority of the North American on-highway fleet. Each one lists its real engine, transmission, and sleeper options.
6 coveredEngines
The major heavy-duty diesel engines powering current Class 8 trucks, with their real horsepower and torque ranges. They are the same engines this site's Fault Code Lookup tool covers for diagnosis.
10 coveredTransmissions
Automated manual transmissions (AMTs) now dominate new Class 8 truck specs. They have largely replaced the traditional manual. Here's what's actually behind each major OEM's badge, plus where a full automatic still makes sense.
6 coveredAxles
The two major suppliers of heavy-duty drive axles for Class 8 trucks, and how their model numbers match real weight ratings.
2 coveredTrailers
The three trailer types that cover the large majority of dry freight movement, with their real standard dimensions.
3 coveredComponents
The major chassis parts that show up on every truck brand, whatever OEM badge is on the hood. They are brake and suspension systems, and they matter in the aftermarket.
2 coveredEngine guides: service intervals, lifespan and common problems
One page per heavy-duty engine, built only from the maker's published documents. The reported trouble spots are kept clearly separate from the official figures.
- Detroit DD15Detroit (Daimler Truck)
- PACCAR MX-13PACCAR
- Cummins X15Cummins
- Volvo D13Volvo
- Mack MP8Mack
- International S13International (Navistar)
- Detroit DD13Detroit (Daimler Truck)
- Detroit DD16Detroit (Daimler Truck)
- PACCAR MX-11PACCAR
- Cummins X12Cummins
Engine comparisons
Transmission guides: gear ratios, fluid and oil change intervals
One page per heavy-duty transmission, built only from the maker's published documents. Where a maker does not publish a number, the page says so.
- Detroit DT12Detroit (Daimler Truck)
- PACCAR TX-12PACCAR
- Volvo I-ShiftVolvo Trucks
- Eaton Cummins EndurantEaton Cummins
- International T14International (Navistar)
- Allison 4000 SeriesAllison Transmission
Transmission comparisons
Class 8 specs at a glance
The tables below put the current North American long-haul equipment side by side. Ranges are real factory option spreads. An engine sold in several horsepower ratings shows its full range, not one number. The category pages above go deeper on each model, engine and part.
| Truck | Engine options | Transmission | Sleeper options |
|---|---|---|---|
| Freightliner Cascadia | Detroit DD13 (370–525 hp) or DD15 (425–505 hp); Cummins X15N (400–500 hp) | Detroit DT12 automated manual (12-speed) | 48", 60", 72" mid-roof; 60", 72" raised-roof |
| Peterbilt 579 | PACCAR MX-13 (405–510 hp, 1,450–1,850 lb-ft) | PACCAR TX-12 automated manual (12-speed) | Up to 80" UltraLoft, the largest factory sleeper from any major OEM |
| Kenworth T680 | PACCAR MX-13 (405–510 hp, 1,450–1,850 lb-ft) | PACCAR TX-12 automated manual (12-speed) | 76" sleeper, widely regarded for build quality and driver comfort |
| Volvo Trucks VNL | Volvo D13: variable-geometry turbo or turbo-compound, 405–455 hp, 1,450–1,850 lb-ft | Volvo I-Shift automated manual: 12- or 13-speed (the only transmission offered behind the D13) | Up to 74" high-rise/stand-up sleeper |
| Mack Anthem | Mack MP7, MP8 (434–505 hp, 1,460–1,760 lb-ft), or MP8HE (415–445 hp, 1,760–1,860 lb-ft) | Mack mDRIVE automated manual | – |
| International LT | S13 Integrated Powertrain: up to 515 hp, 1,850 lb-ft (lightest 13-liter diesel in North America) | T14 automated manual (14-speed, optimized for direct drive), integrated with the S13 | – |
| Engine | Displacement | Horsepower | Torque |
|---|---|---|---|
| Detroit (Daimler Truck) DD15 | 14.8L, inline-6 | 425–505 hp (Gen 5); 425–505 hp with more torque on Gen 6 | 1,550–1,850 lb-ft (Gen 5); 1,650–1,900 lb-ft (Gen 6) |
| PACCAR MX-13 | 12.9L, inline-6 | 405–510 hp | 1,450–1,850 lb-ft |
| Cummins X15 | 14.9L, inline-6 | 336–605 hp depending on series (Efficiency: 400–500 hp; Performance: 485–565 hp; Productivity: 430–605 hp) | 1,450–2,050 lb-ft depending on series |
| Volvo D13 | – | 405–455 hp | 1,450–1,850 lb-ft |
| Mack MP8 | 13L (780 ci), inline-6, overhead cam | 434–505 hp (standard MP8); 415–445 hp (MP8HE) | 1,460–1,760 lb-ft (standard); 1,760–1,860 lb-ft (MP8HE) |
| International (Navistar) S13 | 13L, inline-6 | Up to 515 hp | Up to 1,850 lb-ft |
| Detroit (Daimler Truck) DD13 | 12.8L, inline-6 | 370–525 hp (Gen 5) | 1,250–1,850 lb-ft (Gen 5) |
| Detroit (Daimler Truck) DD16 | 15.6L, inline-6 | 500–600 hp (Gen 5) | 1,850–2,050 lb-ft (Gen 5) |
| PACCAR MX-11 | 10.8L, inline-6 | 355–445 hp | 1,250–1,700 lb-ft |
| Cummins X12 | 11.8L, inline-6 | 350–500 hp | 1,250–1,700 lb-ft |
| Transmission | Type | Pairs with / rating |
|---|---|---|
| Detroit (Daimler Truck) DT12 | Automated manual (AMT), 12-speed | Detroit DD13, DD15 |
| PACCAR TX-12 | Automated manual (AMT), 12-speed | PACCAR MX-13 |
| Volvo I-Shift | Automated manual (AMT), 12- or 13-speed | Volvo D13 only |
| Eaton Cummins Endurant HD / XD | Automated manual (AMT) | Up to 1,850 lb-ft |
| International (Navistar) T14 | Automated manual (AMT), 14-speed | International S13 only |
| Allison 4000 Series | Full automatic (torque converter, not clutch-based) | Up to 2,360 lb-ft |
| Trailer | Standard length | Width | Height / deck |
|---|---|---|---|
| Dry Van | 48' or 53' (53' is most common today) | 102" (8.5') | ~110" (varies by spec) |
| Reefer (Refrigerated) | 48' or 53' | 102" (8.5') | ~13.5' overall |
| Flatbed | 48' | ~102" | 60–62" (leaving 8'4"–8'6" of legal load height) |
How to read a truck spec sheet
- Horsepower vs. torque
- Horsepower is how fast the engine can do work. Torque, measured in lb-ft, is the twisting force it delivers. Heavy-duty diesels are rated on both. The engine tune (its rating within a range) decides which one you get more of. Compare ratings within the same range, not peak numbers across brands.
- GVWR and GAWR
- GVWR (gross vehicle weight rating) is the most the whole truck is rated to weigh. GAWR (gross axle weight rating) is the same limit for a single axle. They are maker ratings for what the equipment can carry. That is separate from what is legal on the road.
- Federal weight limits
- On the Interstate System the federal limits are 80,000 lb gross vehicle weight (23 CFR 658.17). The limit is 20,000 lb on a single axle and 34,000 lb on a tandem axle group. A truck can have axles rated well above 34,000 lb. It is still limited to that on the Interstate. So payload planning starts from the legal limit, not the axle tag.
- Automated manual vs. automatic
- An automated manual (AMT) is a manual gearbox with a computer-controlled clutch and shifter. A full automatic uses a torque converter instead. Most new long-haul tractors are ordered with an AMT. The transmissions table above shows which engines each one is built around.
Also on Grow Trucking
Want a dispatcher to handle this for you?
Grow Trucking finds loads, negotiates rates and does the paperwork for owner-operators and small fleets. Tell us about your truck and we will show you how we can help.
Also: About Grow Trucking · Refer a carrier · Trucking blog