The Paccar TX-12 Pro automated transmission. (Paccar)
Peterbilt will make powertrains with a TX-12 Pro automated transmission and Paccar MX-13 engine combination an option available to buyers of its 579, 567 and 589 tractors, the Paccar unit said March 25.
Peterbilt’s flagship Model 579 tractor is available with an MX-13 or MX-11 engine.
The Model 579 is also available with the Paccar TX-12, TX-18, TX-18 Pro, plus Eaton automated and manual transmissions.
Operating with the MX-13 engine, the TX-12 Pro supports up to 1,700 pound-feet of torque and is aimed at uses such as dump trucks, tankers or municipality vehicles, Peterbilt said.
“The seamless integration of the TX-12 Pro transmission and the Paccar MX-13 engine creates a robust powertrain configuration for many types of on-highway and vocational applications,” said Erik Johnson, assistant general manager of sales and marketing for Peterbilt. “This advanced powertrain delivers superior fuel efficiency and uptime for our customers.”
Jake Montero (left) and Erik Johnson (Peterbilt)
Peterbilt said the TX-12 Pro is engineered to operate with engines that have up to 1,000 pound-feet of torque and a maximum gross combination weight rating of 70,000 pounds.
The transmission has dual power takeoff functionality to enable multiple hydraulic devices to operate simultaneously; an extreme duty clutch for low-speed maneuvering with higher loads; and a rock-free mode that helps rock the truck free from mud, sand or snow.
TX-12 Pro was introduced for heavy-duty and medium-duty Peterbilt models in March 2024.
In August 2024, Peterbilt began offering both TX-12 and TX-12 Pro automated transmissions with PX-9 engines for its Models 548, 537 and 536.
“Together, the TX-12 transmissions and PX-9 engine, create an exceptional combination of efficiency and reliability,” Jake Montero, then assistant general manager of sales and marketing, said at the time.
“Our medium-duty customers can spec confidently knowing this new powertrain configuration delivers increased productivity and an excellent driving experience,” he added.
Paccar promoted Montero in January to be the top executive at Peterbilt. Montero replaced Jason Skoog, who had held the general manager position since March 2018. In a Jan. 27 post on LinkedIn, Skoog said he was stepping aside to spend more time with his children after a 2024 that “was particularly challenging and difficult.”
A TX-12 and PX-9 engine combination operates up to 1,250 pound-feet of torque with a maximum GCWR of 66,000 pounds and is aimed at pickup and delivery customers. A PX-9 and TX-12 PRO combination supports up to 1,250 pound-feet of torque and a maximum GCWR of 66,000 pounds and is seen as more useful for snowplows, cranes and bucket/boom trucks.
The Model 589 is available with Paccar MX-13 and Cummins X15 engines plus Eaton RT and FR Manual, TX-12/Endurant, TX-18/Endurant XD or Allison 4000/4500/4700 transmissions.
Peterbilt’s Model 567 is available with MX-13, 11 or PX-9 plus Cummins X15 diesel engines, or the natural gas Cummins ISX12N and L9N engines.
Peterbilt 579 with the CARB-compliant Paccar MX-13 engine. (Peterbilt)
A California Air Resources Board-compliant low nitrogen oxide MX-13 engine is also available for Models 579, 567 and 589. (The main difference is a larger-volume aftertreatment system.
Two CARB-compliant options can be purchased: a high-performance 510-horsepower rating with 1,850 pound-feet of torque and an efficiency-focused rating of 455 horsepower and 1,650 pound-feet of torque between 900 and 1,325 rpm.
