Best of both worlds?
A clutch pedal and shifter may soon become as anachronistic as buttons on a phone.
Industry trends on new trucks show that automated manual transmissions are outpacing traditional manual transmissions by more than 2-to-1 and are becoming “the norm” for linehaul and on-highway applications.
What’s the difference between AMT, manual and automatic?
Automated manual transmissions, or AMTs, are more like their manual predecessors than a traditional automatic transmission. In fact, AMTs utilize a manual gearbox, with a clutch and gearshifts, rather than planetary gearing with disc packs and torque converters in a true automatic transmission. The difference between an AMT and a true manual is that a computer does the shifting instead of a human.
Original equipment manufacturers like Paccar and Daimler tout the benefits of AMT transmission over strictly manual transmissions by making driving more accessible to new drivers who may be unfamiliar with manual shifting and also letting veteran drivers focus on the road instead of on shifting. The OEMs say the automated transmissions also provide more optimized shifting than a traditional automatic, improving fuel economy. The manual gearbox is lighter than an automatic transmission, leading to weight savings and the ability for drivers to apply the extra pounds to cargo payload.
A new normal
Automated transmissions have become the norm in on-highway applications, said Kurt Swihart, Kenworth marketing director.
“In 2017, the ratio was 70 percent automated transmissions and 30 percent manual transmissions for the Kenworth T680, our on-highway flagship truck. It’s running at about the same rate so far in 2018,” Swihart said. “Five years ago, only about 30 percent of our linehaul customers purchased automated transmissions.”
For several years, Peterbilt has seen a steady incline of customers ordering trucks equipped with an automated transmission. In fact, today more than 75 percent of customers ordering Peterbilt’s flagship on-highway Model 579 spec an automated transmission, according to the truck maker. Customers who order these transmissions do so for several reasons, including superior fuel economy numbers, ease of maintenance, and driver recruitment/retention, according to a Peterbilt spokesperson.
Blank slate design
Paccar’s automated transmission is not a conversion of a manual transmission but rather a blank-slate design. That means every aspect of its performance was optimized for on-highway applications. The integrated transmission constantly monitors road grade, vehicle speed, acceleration, torque demand, weight and engine load to quickly make smooth fuel-efficient gear selections. Because of this, both Kenworth and Peterbilt tell customers they can expect to see a significant increase in fuel economy.
Swihart says the appeal of automated manual transmissions isn’t limited to just new drivers who are unaccustomed to the idea of gripping a gear shift knob. He says veteran drivers can also benefit from the technology in a variety of ways, including weight savings, less fatigue and improved fuel mileage.
“Automated transmissions are becoming very popular, even among senior drivers who said they’d never go with an automated. Once they’ve tried it, they don’t want to go back,” Swihart said. “For example, the proprietary 12-speed Paccar automated transmission – seamlessly integrated with the Paccar MX-13 engine and Paccar tandem rear axles in the Kenworth T680 – benefits truck operators by providing new efficiencies in fuel economy and weight savings.”
Designed from the ground up, the Paccar transmission is up to 105 pounds lighter than comparable transmissions, allowing for greater payloads. “The Paccar transmission also offers the best overall gear ratio coverage and provides excellent low-speed maneuverability,” Swihart said.
Kenworth also offers the 12-speed Paccar transmission and right-hand column-mounted shifter as standard equipment on linehaul and regional haul applications of Kenworth’s on-highway flagship T680. “The column-mounted shifter for the Paccar transmission places gear selection and engine brake controls at the driver’s fingertips for better ergonomics, comfort and overall performance. With the shifter right there on the steering column, the driver does not have to reach for it. This placement also frees up dash space by eliminating engine brake control switches,” Swihart said.
The Paccar transmission provides a 750,000-mile oil change interval that is the longest available for linehaul applications. Other features include a maintenance-free clutch, and an internally routed electrical system that minimizes exposure to the elements. The fluid pressure detection system protects the gears from low fluid conditions. The transmission is ideal for linehaul and regional haul applications up to 110,000 pounds gross vehicle weight.
“The proprietary Paccar Powertrain – which includes Paccar’s 12.9-liter MX-13 and 10.8-liter MX-11 engine, 12-speed Paccar transmission and Paccar 40K tandem rear axles – provides outstanding performance through weight savings, increased fuel efficiency and enhanced driveability for Kenworth T680s operating in linehaul and regional haul applications,” Swihart said. LL