Kenworth is expanding its powertrain offerings by introducing the Paccar TX-12 PRO automated transmission paired with the MX-13 engine for its T680, T880, and W990 Class 8 trucks. The move aligns with Kenworth’s strategy to offer more integrated, high-performance solutions for both on-highway and vocational applications.
Previously, the TX-12 PRO transmission an advanced automated gearbox designed for durability and efficiency was only offered with the PX-9 and MX-11 engines in the T680 and T880. With this latest update, the pairing of TX-12 PRO and MX-13 brings increased power and torque availability, offering up to 455 horsepower and 1,650 lb.-ft. of torque, while accommodating gross combination weights of up to 70,000 pounds.
Expanded Powertrain Configurations
Kenworth’s flagship T680 on-highway tractor now supports a broad array of engine and transmission combinations:
- Engines: Paccar PX-9, MX-11, MX-13; Cummins X15
- Transmissions: Paccar TX-12, TX-12 PRO, TX-18, TX-18 PRO; Eaton Endurant HD, XD, XD Pro
The T880 vocational truck, Kenworth’s workhorse for construction and municipal duties, is similarly equipped with:
- Engines: PX-9, MX-11, MX-13; Cummins X15
- Transmissions: Paccar TX-12, TX-12 PRO, TX-18, TX-18 PRO; Eaton Endurant HD, XD, XD Pro; Allison automatics
The long-hood W990, designed with classic styling cues but modern performance, also benefits from the update:
- Engines: MX-13; Cummins X15
- Transmissions: TX-12, TX-12 PRO, TX-18, TX-18 PRO; Eaton Endurant HD, XD, XD Pro; Allison automatics
These enhanced options offer fleets increased flexibility for tailoring trucks to specific duty cycles, whether long-haul, heavy-load, or mixed vocational use.
TX-12 PRO: Built for Vocational Demands
The TX-12 PRO transmission is engineered to support demanding vocational tasks. It features an extreme-duty clutch for improved low-speed maneuverability, and includes “rock-free mode” functionality to assist trucks in regaining traction when stuck in loose terrain. These features make it especially valuable for construction, refuse, and utility service fleets.
“The integration of the TX-12 PRO transmission with the MX-13 engine is a significant enhancement for our vocational customers,” said Kevin Haygood, Kenworth Assistant General Manager for Sales and Marketing.
This expansion follows a similar move by Peterbilt, Kenworth’s sister company under the Paccar umbrella, which introduced the TX-12 PRO and MX-13 combination to its Model 579, 567, and 589 trucks in March 2024.
Focus on Electrification and Model Evolution
The introduction of this new powertrain combination is part of a broader product modernization at Kenworth. In April 2025, Kenworth launched a redesigned T680E, its second-generation Class 8 battery-electric truck, at the Advanced Clean Transportation Expo in Anaheim, California. The vehicle, featuring Paccar’s in-house developed ePowertrain (delivering up to 605 peak horsepower and 1,850 lb.-ft. of torque), is available in a 6×4 day cab configuration as either a tractor or straight truck.
Kenworth also introduced the T880E, its first battery-electric vocational truck, reflecting the company’s commitment to zero-emissions solutions for both highway and vocational segments.
The first generation of the T680E debuted in 2020 as Kenworth’s initial foray into Class 8 battery-electric vehicles.
Transitioning Legacy Models
As part of this strategic overhaul, Kenworth will discontinue three legacy 1.9-meter cab models in 2026: the iconic W900, T800W, and C500. The W900, a cornerstone of Kenworth’s identity since 1963, will be phased out in favor of modern alternatives like the W990 and T880.
Orders for these retiring models will conclude in late 2025. This mirrors a broader shift at Paccar, which has also ended production of other heritage models like Peterbilt’s Model 389, replaced by the newer Model 589 in early 2024.
Hydrogen Truck Production Delayed
On the alternative fuels front, Kenworth has delayed the serial production of its hydrogen fuel cell T680, developed in partnership with Toyota. Although previously scheduled for 2025, the timeline is now under review. According to Kenworth Chief Engineer Joe Adams, the company is still calibrating the powertrain and evaluating the supporting infrastructure necessary for successful deployment.
The delay underscores ongoing challenges for hydrogen-powered Class 8 trucks in the U.S., including infrastructure readiness and cost efficiency.
Kenworth’s expanded powertrain options, combined with its push into electrification and streamlining of its truck portfolio, illustrate the company’s commitment to innovation and market adaptability. With more efficient diesel configurations, electric alternatives, and plans for hydrogen integration, Kenworth is positioning itself to meet the evolving demands of commercial trucking across multiple industries.
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