Gasoline Power Returns to North American Medium-Duty Trucks as Cummins B6.7 Octane Enters Production
Cummins' first purpose-built commercial gasoline engine, the B6.7 Octane, is entering production for North American medium-duty trucks. Daimler Truck North America opened ordering for the engine in the Freightliner M2 106 in the week of March 9, 2026, with start of production scheduled for the third quarter of 2026, and Kenworth will offer it across its Class 5-7 conventional trucks. For fleets and the shops that service them, the move adds a gasoline option that drops diesel aftertreatment hardware entirely, and it signals a wider shift in what medium-duty powertrains will look like through the EPA 2027 era.
What Happened
The B6.7 Octane is Cummins' first commercial-grade gasoline engine, built on the company's HELM platform architecture and validated against the same standards as the diesel B6.7. It runs on regular 87-octane gasoline and uses a simple three-way catalyst, so there is no DEF, no active regeneration, and no diesel aftertreatment hardware to maintain.
- Output: up to 300 horsepower and 660 lb-ft of torque, aimed at vocational, pickup-and-delivery, and urban duty cycles.
- Efficiency: Cummins rates it up to 10 percent more fuel efficient than comparable gasoline engines, with oil-service intervals of up to 15,000 miles.
- Compliance: EPA 2027 certified and meets CARB low NOx regulations, which positions it for California and other CARB-aligned states.
| OEM | Truck Application | Transmission Pairing | Timing |
|---|---|---|---|
| Freightliner (DTNA) | M2 106 / M2 106 Plus medium-duty | Allison 9-Speed automatic | Ordering opened March 2026; production from Q3 2026 (Allison pairing from July 2026) |
| Kenworth (PACCAR) | Class 5-7 conventional trucks | PACCAR TX-8 automated | First shown at NTEA Work Truck Week 2025; orderable for current production |
DTNA has also confirmed the B6.7 Octane as part of a six-engine Cummins lineup for its 2027-model Freightliner and Western Star trucks, alongside the new X10, the redesigned X15, and the carryover B6.7 diesel, L9N, and X15N natural gas engines.
Why Gasoline, and Why Now
Medium-duty buyers have been asking for simpler emissions hardware. A gasoline engine with a three-way catalyst meets strict EPA 2027 and CARB low-NOx rules without the DPF, DEF dosing, and parked regenerations that add cost and downtime on diesel trucks in stop-and-go duty. Gasoline also suits fleets whose facilities and drivers are already set up for gas vehicles, such as lease and rental operators, landscapers, and P&D fleets, according to Kenworth.
What It Means for Fleets and the Aftermarket
- Less aftertreatment to service. Gasoline medium-duty units eliminate DPF cleaning, DEF quality issues, and regen-related downtime, the most common diesel service complaints in urban cycles.
- Diesel still carries the heavy work. The B6.7 Octane tops out at 300 hp for Class 5-7 applications. Class 8 line-haul and heavy vocational trucks remain diesel territory, and Cummins' 2027 diesel lineup (X10, redesigned X15) continues in parallel.
- A slow shift in the parts mix. As gasoline medium-duty volume builds, expect gradual change in demand for aftertreatment components on Class 5-7 trucks, while core diesel wear items, including turbochargers, injection, and filtration, remain tied to the large and growing diesel parc.
- Watch total cost, not just simplicity. Gasoline trades fuel economy for lower maintenance. The math favors short-route, high-idle duty cycles, which is exactly where diesel aftertreatment causes the most grief.
Where UPAPSI Fits
Gasoline's return to medium duty does not change the core of the North American truck parc: tens of millions of diesel trucks, from Cummins-powered pickups to Class 8 tractors, still depend on turbochargers that wear, fail, and need fast replacement. That is where we work. UPAPSI supplies brand-new replacement Cummins turbochargers from US warehouse stock, with a one-year unlimited-mileage warranty and no core charge. If a unit on your lot needs a turbo, send us the OE part number or engine serial number and we will confirm fitment before you order.
Sources
- Daimler Truck North America, "Daimler Truck North America Expands Engine Portfolio with New Cummins Lineup," March 9, 2026
- Kenworth Truck Company, "New Cummins Gasoline Engine for Kenworth Medium Duty Trucks Meets All 2027 EPA and CARB Requirements," March 5, 2025
- Transport Topics, "DTNA to Offer 6 Cummins Engines in 2027 Lineup," March 11, 2026
- Allison Transmission, "Daimler Truck North America partners with Allison Transmission to deliver advanced propulsion solutions for Freightliner M2 106 Plus," March 10, 2026
- Heavy Duty Trucking, "Kenworth Announces New Cummins Engine for Medium-Duty Truck Line," March 5, 2025
