Paccar TX-18 transmission ready for vocational demands

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Paccar has unveiled its latest automated transmission (AMT) in the form of the vocational TX-18 designed for on- and off-highway applications.

It was developed through a partnership with Eaton.

The TX-18 vocational gearbox is optimized for on-highway, high-performance, and mild vocational applications. Its counterpart, the TX-18 Pro, is engineered for on- and off-highway work in mild-to-severe applications.

Model 567 Peterbilt
The new TX-18 Pro AMT was able to power this Peterbilt Model 567 loaded to 140,000 lb. around the snowy Eaton Proving Grounds in Marshall, Michigan, including climbing and descending a 15% grade. (Photo: Jack Roberts)

As of July 2022, the new transmissions will be available in the Kenworth T680 Next Gen, T880, T800S, and W990, as well as Peterbilt Models 567, 579 and 389.

Kenworth offered a sneak peak of its latest transmission in January, outfitting a Kenworth T680 with a TX-18 for brief test drives in city traffic. And the transmission was officially launched a couple of weeks later at Eaton Proving Grounds outside Marshall, Mich.

“The TX-18 is designed for heavy-duty applications, with both versions rated up to 140,000 lb. GCWR,” said Peterbilt vocational product manager Kyle Crawford said during the pre-drive briefing on the new AMTs. “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.”

Crawford said features on the new AMTs include an extreme-duty clutch, an 1,850 lb-ft torque rating, and 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 horspower 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.”

Design features

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 features 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.

Other important vocational features listed by Crawford include an integrated clutch housing, a transmission cooler option for cross combination weight ratings under 110,000 lb., internal wiring and sensors to protect against the elements, and a standard oil temperature sensor.

Driver feedback on the new TX-18 and TX-18 Pro have been positive as well, Crawford noted. “Drivers tell us they like the transmission’s excellent low-speed maneuverability; its small and even gear steps; and its simple, easy-to-use, next-generation controls, which include a stalk-mounted shifter.”

Another important feature Crawford pointed out is the TX-18’s “optimal” clutch engagement for hill starts – even with 160,000 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 downgrades. 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.”

Paccar TX-18 and TX-18 Pro quick spec’s

                                                                       TX-18                                     TX-18 PRO

Max. Horsepower                                           510 HP                        510 HP

Max. Torque Capacity                        1,850 lb-ft                             1,850 lb-ft

Max. Operating Weight (GCWR)        140,000 lbs.                            140,000 lb.

Unit Weight                                                    808 lbs.                                   813 lbs.

Oil Capacity                                                    12 liters                       12 liters

Maintenance Intervals (on-highway):            500,00 miles or 5 years

Vocational Lube Interval:                               250,000 miles or 3 years

Clutch:                                                            Maintenance-free

  • Clarification: This article has been updated to remove a reference to the TX-8 medium-duty transmission that was developed with ZF rather than Eaton.
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Jack Roberts has been covering the North American trucking and transportation industries as a journalist since 1995. A licensed commercial driver, Roberts has emerged as a leading authority on new and advanced logistics and vehicle technologies, including autonomous vehicle systems, battery-electric trucks, and hydrogen fuel cells. Roberts is a graduate of the University of Alabama and lives and works in Tuscaloosa, Alabama.

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