Photo © PACCAR Inc., Kenworth. All rights reserved.

Photo © PACCAR Inc., Peterbilt. All rights reserved.

New and Only CARB-Compliant Fully Automatic Transmission and Diesel Engine Pairing to Deliver Lower Emissions While Maintaining Optimized Performance for Heavy-Duty Vehicles

INDIANAPOLIS, July 29, 2025 - Allison Transmission is pleased to announce the Allison 4000 Series™ fully automatic transmission is now available with the new CARB low NOx compliant PACCAR MX-13 engine for Kenworth T880 and Peterbilt Model 567 truck models. The Allison 4000 Series™ is the only fully automatic transmission available with the MX-13 engine that is CARB-compliant and the pairing is designed to optimize performance and reduce NOx emissions.

"Integrating the Allison 4000 Series into vehicles equipped with the CARB-compliant PACCAR MX-13 engine will support efficiency and fuel economy, while still delivering on our promise of reliability and productivity,” said Rohan Barua, Vice President, North America Sales, Global Channel and Aftermarket, Allison Transmission. “Our proven history of exceeding customer expectations across a wide range of vehicle applications positions us to support the changing dynamics of future powertrains and Improve the Way the World Works."

The Allison 4000 Series transmission is widely used across multiple commercial vehicle applications, including construction, energy, mining, defense and vocational trucking. It is available in various configurations, offering six or seven forward gears depending on the model.

The 4000 Series transmission is designed to provide an ideal balance of performance and fuel efficiency, leveraging Allison's torque converter to multiply engine torque significantly improving startability, drivability and overall productivity.

Additionally, Allison’s FuelSense^® 2.0 technology is available on the Peterbilt Model 567 and standard on Kenworth T880 truck models. It is an advanced fuel-efficiency technology suite designed to optimize performance in automatic transmissions for commercial vehicles. It dynamically adjusts shift points and torque based on load and driving conditions, providing quantifiable fuel savings of up to 6%. Allison. Key features, such as DynActive® Shifting, Neutral at Stop, and Acceleration Rate Management, work together to minimize energy losses and enhance overall vehicle efficiency.