Street Smarts: Paccar bulks up AMT line

04 August 2022

The North American vocational truck market is extremely important to both the Kenworth and Peterbilt truck companies. And the two OEMs’ parent company, Paccar, has been working hard to offer new, advanced powertrain components that will keep Kenworth and Peterbilt work trucks efficient and durable even in tough on- and off-highway applications.

Jack Roberts is a Tuscaloosa, Ala.-based independent journalist and licensed commercial driver with more than 20 years’ experience covering the North American and global trucking industries.

The new TX-18 automated manual transmission (AMT) family is a prime example of this ongoing engineering effort. The TX-18 and its more robust TX-18 Pro big brother are both based on Paccar’s TX-8 medium-duty and TX-12 heavy-duty vocational automated transmissions. Naturally, the new AMTs are optimized for Paccar’s MX series of diesel engines for optimal fuel economy and on-demand power when hauling heavy loads or dealing with difficult ground conditions.

The new TX-18 gearbox is optimized for on-highway, high-performance and mild vocational applications, with the new TX-18 Pro version engineered for on- and off-highway work in mild to severe applications. The AMTs will be available as a spec for the following model trucks:

  • Kenworth – T680 Next Gen, T880, T800S and W990
  • Peterbilt – Model 567, Model 579 and Model 389

“These new transmissions are based on the Paccar TX-8 and TX-12 transmissions, which are getting great reviews for their passenger car-like performance and feel,” Kyle Crawford, vocational product manager for Peterbilt, said during the official launch of the new gearboxes earlier this year. “The TX-18 is designed for heavy-duty applications, with both versions rated up to 140000 lb. GCWR. So, it’s designed for heavy-duty applications like off-highway construction, heavy-duty wreckers and fleets that haul in mountainous terrain and need a little more power and performance to deal with those conditions.”

Among the new features available on the TX-Series, Crawford called out a new extreme-duty clutch, an 1850 lb.-ft. torque rating as well as six reverse gears for the extreme-duty TX-18 unit. “Those six reverse gears on the TX-18 are combined with a standard dual power-takeoff (PTO),” he added. “The PTO provides 75 to 160 hp and can be operated while driving – so when combined with the TX-18’s six reverse gears, makes it an excellent choice for rock-spreading applications.”

Additionally, Crawford said the TX-18 design features a 47% reduction in parasitic losses and is 225 lb. lighter than competitive AMTs on the market. It also incorporates predictive cruise control, is fully integrated with current Paccar powertrain technology and systems and can be programmed with four different application-specific calibrations to ensure peak performance in difficult applications.

“With these transmissions, we can deliver smooth highway cruising on par with the performance offered by the TX-12,” Crawford said. “But at the same time, the TX-18 and TX-18 Pro offer a range of vocational features and performance that allow them to excel in extreme applications. So, we really feel like these transmissions deliver the best of both worlds for fleets and drivers, regardless of whether the truck is on the highway, or working hard out in the oilfields.”

Other important vocational features on the TX-Series include:

  • An integrated clutch housing.
  • A transmission cooler option for GCWR ratings under 110000 lb.
  • Internal wiring and sensors for added protection from the elements and enhanced uptime.
  • A standard oil temperature sensor.

Another important feature Crawford pointed out is the TX-18’s “optimal” clutch engagement for hill-starts – even with 160000 lb. on a flatbed behind the truck. “The AMT automatically holds the truck still when the brake is released and then selects the best gear possible to start and gain speed going uphill,” he explained. “The transmission will also automatically select the proper gear for holding the truck at a steady speed on down grades. This is a big benefit from a safety standpoint, while helping reduce driver fatigue. It also helps expand a fleet’s potential driver pool by making good drivers even better in difficult terrain conditions.”

Both new transmissions will be available at Kenworth and Peterbilt dealerships beginning in July of this year.


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