Kenworth and Peterbilt are adding an 18-speed automated transmission to their respective product suites for on-highway and select off highway vocational applications.

The Eaton-manufactured Paccar TX-18 and Paccar TX-18 Pro automated transmissions are available with the Kenworth T680, T880 and W990 and Peterbilt models 567, 389 and 579 equipped exclusively with MX-13 and MX-11 engines.

Paccar said the two new offerings are software calibrated to optimize the Paccar MX engine platform and maximize the full potential of all MX engine ratings, with maximums of 510 horsepower, 1,850 lb.-ft. of torque capacity and 140,000 pounds of gross combination vehicle weight (GCVW).

The TX-18 offers additional capability for heavy on-highway use for applications, such as heavy haul transport. The TX-18 Pro adds enhanced capabilities and unique features for extreme duty vocational applications and other select off-highway applications.

“Drivers will appreciate the versatility of the Paccar TX-18 and Paccar TX-18 Pro that deliver excellent low-speed maneuverability," said Jim Walenczak, Kenworth assistant general manager for sales and marketing. "Both seasoned and new drivers will benefit from tailored configurations that help them get the job done, and new performance calibrations that expertly control transmission shift points."

The TX-18 features a high-pressure diecast aluminum casing, one-piece serviceable input shaft, helical gearing, precision lubrication system, extreme duty clutch and an integrated clutch housing and can be configured with an optional transmission cooler. The transmission features 4 application-specific calibrations and comes standard with two PTO openings capable of a combined 160 hp.

The TX-18 has three reverse gears, and TX-18 Pro has six, which pairs well with deep axle ratios.

Both transmissions offer expanded high-capacity PTO functionality with an 8-bolt bottom mount and 4-bolt rear mount for a combined 160 hp capacity at 1,400 RPM. The transmissions are equipped with an internal oil temperature sensor. The sensor shows transmission temperatures on the in-cab 15-inch digital display and provides driver notifications in situations causing excessive temperatures.

The TX-18 and TX-18 Pro are standard with and automotive-style, stalk-mounted shifter with Drive, Neutral, Reverse and Manual modes.

On-highway maintenance intervals are 500,000 miles or five years, and vocational intervals are 250,000 miles or three years for the TX-18 and TX-18 Pro. The transmissions utilize a maintenance-free clutch.

"The gains in productivity, efficiency, uptime and the ease of use for drivers make these transmissions a must-have,” added Jacob Montero, Peterbilt general sales manager.