Manual transmissions… still shifting?

Nov 20, 2023

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According to Edmunds.com, manual transmissions were sold on just 2 percent of all automobiles sold in the U.S. in 2018, an article in the Chicago Tribune reported. In 2006, 47 percent of new auto models in the U.S. were offered with automatics and manuals. Now it's down to 20 percent and dropping sharply.

"For automakers it will be simpler when the manual dies," said Ivan Drury, senior analyst at Edmunds.com. "It's kind of a hassle for them to offer both; same with dealers. Given the market forces, it's going to go away."

The percentage of Class 8 trucks, or semi-trucks (those with a gross vehicle weight rating exceeding 33,000 pounds) equipped with manual transmissions is certainly much higher than the consumer automobile market. However, that percentage has declined (and is declining). But Class 8 trucks with manual transmissions are still manufactured – and preferred by many drivers.

According to a 2018 article in the Minneapolis Star-Tribune, the majority of trucks now being built are outfitted with automated manual transmissions, or AMTs, which are more efficient and quicker to learn at a time when trucking companies seek to lower costs and also face an ongoing shortage of qualified drivers. In the place of a "real" manual transmission (one that the driver uses in combination with a clutch to actually shift through the gears) is the AMT, equipped with a computer that automates gear-shifting. It's more similar to the automatic transmissions common in cars and light trucks than it is to a manual transmission. And like a car's automatic transmission, it frees a driver from shifting gears.

"Manual transmissions continue to be a very reliable and cost-effective means for companies and professional drivers," Shane Groner, director of field business development for the Eaton Vehicle Group, explained to American Trucker. "Manual transmissions currently continue to make up approximately 50 percent of the total North American Class 8 market."

As writer Adam Belz of the Star-Tribune wrote, "regional and local trucking companies that use older trucks may hold on to manual transmissions longer, but the days of a trucker gear-jamming down the interstate in a 36-speed are coming to an end."

Not so fast. Despite the rise in popularity of AMTs and fully automatic gearboxes, the days of the tried-and-true manual shifter may be numbered. However, according to truck manufacturers and suppliers, that is not the case – at least not yet.

"Manual transmissions continue to be a very reliable and cost-effective means for companies and professional drivers," Shane Groner, director of field business development for the Eaton Vehicle Group, explained to American Trucker.

Groner continued, "Manual transmissions currently continue to make up approximately 50 percent of the total North American Class 8 market. While that number will decline over time due to fleets transitioning to automation to enable a larger driver pool population, it is not expected that automated transmissions will fully displace manual transmissions in the foreseeable future."

Groner's remarks were echoed by Kelly Gedert, manager of Detroit powertrain and components marketing for Daimler Trucks North America (DTNA). "While there is a ‘noticeable movement’ towards more use of AMTs and fully automatic gearboxes, manuals will continue to be offered as they are demanded based on customer preference and type of application."

Gedert also said, "In 2017, for example, our Detroit DT12 AMT was ordered on approximately 70 percent of all combined Freightliner Cascadia and Western Star 5700XE on-highway models, but manuals were still ordered on 20 percent to 25 percent of all transmissions sold in all Freightliner and Western Star models." He added, "The use of manuals is typically dictated more by customer/driver preference than by application. The ever-increasing availability and technical coverage of AMTs and automatics, such as the release of the rear-mount power take-offs [PTOs] on the Detroit DT12, is expanding coverage for many additional applications."

So unlike the auto and light truck markets, the strictly manual transmission is not disappearing from the cabs of Class 8 trucks – at least not yet. But the numbers of them are declining, and the strong economy is one reason why. A generation of younger drivers who didn't learn to drive in cars with manual transmissions is another reason.

John Moore, product marketing manager-powertrain for Volvo Trucks North America (VTNA), provided information about manual transmissions. "Manual transmissions are not a thing of the past but face ever-mounting pressure from AMTs and full automatics as enhancements are made to these transmissions that allow them to operate in areas that were restricted in the past," he explained.

"For example, our 13- and 14-speed I-Shift with crawler gears was developed to allow it to be used in applications that required a deep reduction start gear for startability on soft ground or sand, or applications that have to back up at a crawl speed to connect to an expensive trailer without damaging it," Moore said.

"Manuals were preferred in the past because the driver could use the clutch to slowly engage the driveline – something AMTs could only dream about until now," he stressed.

Nonetheless, Moore told American Trucker that it will be "quite some time" before manual transmissions are completely replaced by AMTs and fully automatic gearboxes simply because of customer preference. "Despite its prevalence in 90 percent percent of all trucks we build, not everyone has bought into the AMT revolution for various reasons," he noted. "Some drivers just like to shift."

Bryan Berg drives a semi with a 13-speed transmission, and he's been double-clutching and shifting gears in his rig for 30 years. He's not about to start driving a truck that shifts automatically. He told the Star-Tribune, "I just think it would be weird. Most of the drivers I know, they all say automatics are for people who don't know how to drive a truck."

Another driver, Abdullahi Abdulle, from Columbus, Ohio, explained to the Star-Tribune's Belz that he doesn't mind shifting gears. In fact, it helps keep him alert, he said. "Automatic, you just relax, and when you relax, you may take a nap. On the road."

"Manual transmissions are not a thing of the past but face ever-mounting pressure from AMTs and full automatics as enhancements are made to these transmissions that allow them to operate in areas that were restricted in the past," explained John Moore, product marketing manager-powertrain for Volvo Trucks North America (VTNA). "Manuals were preferred in the past because the driver could use the clutch to slowly engage the driveline – something AMTs could only dream about until now."

AMTs vs. automatic transmissions

So non-manual transmissions have faced a challenge with at least some truck drivers in the commercial truck market. Manufacturers have worked to contrast AMTs that offer the convenience of not having to shift gears to traditional automatic transmissions. While they sound similar, in commercial trucks the two utilize different systems.

Historically, manual transmissions have provided an added degree of control that made them preferred by truck drivers. Many early models of automatic truck transmissions had trouble "communicating" with engines, leading to uneven shifts and frustrations from drivers.

According to American Trucker, AMTs operate differently from a pure automatic transmission. AMTs utilize a manual gearbox, with the clutch and gearshifts controlled by an electronic system. By contrast, a traditional automatic uses planetary gearing with disc packs and torque converters.

Automatic transmission benefits

So many drivers (particularly those that have been driving for years or even decades) continue to prefer manual transmissions, there are several benefits that come with either an automatic transmission or an AMT. Because many newer drivers have little or no experience with manual transmissions, automatics add accessibility for these drivers.

Fleet owners see the attraction of these transmissions as well. Automatic transmissions help with driver recruitment and retention, and also help improve fuel economy and safety. An automatic gives the driver the ability to focus more attention on the road, and also helps reduce driver fatigue.

However, early versions of an automated transmission annoyed drivers. The computer would shift too late or too soon, and experienced drivers wanted nothing to do with being a passenger in a truck driven by a novice software program.

Ken Steinfest, an 81-year-old who still drives a semi with a 13-speed manual transmission told the Star-Tribune, "I drove one [automatic transmission] probably 10 years ago, and I didn't like it."

But the technology has improved in recent years.The new transmissions are now better integrated in the trucks and the computers have gotten more precise, evaluating engine torque, engine speed, vehicle speed and vehicle angle before shifting gears.

"Being able to get a driver and get them into a truck and trained and up and running as fast as possible becomes very valuable to a lot of companies," said Wesley Slavin, on-highway marketing manager for Peterbilt, which now produces nearly 90 percent of its trucks with an automated transmission.

The computers controlling automated transmissions can "down-speed" – lower the revolutions per minute of the engine at high speed – effectively and are therefore better at controlling diesel consumption and emissions. While very experienced drivers can coax close to the same mileage from a manual transmission that a computer can get, new drivers cannot. As Slavin noted, "It just shifts and you don't notice."

Rates of adoption for AMTs/automatics

According to Brian Daniels, manager of Detroit Powertrain and component products for Daimler-Benz (which makes Freightliner trucks), better products came on the market around 2015 and demand for them has risen quickly ever since. About 85 percent of Freightliner's semi-trucks now have automated transmissions, up from about 10 percent five years ago.

"There are still the diehards out there, but there's some conversion happening of the diehards, too," Daniels said.

European trucking companies adopted automated transmissions earlier than those in the U.S. for a variety of reasons (regulations, the cost of diesel, miles driven, etc.). Volvo introduced its I-shift transmission in Europe in 2002, and by the late 2000s about 75 percent of its trucks in Europe were manufactured with an automated transmission.

Acceptance of AMTs and/or automatic transmissions continues to grow in the U.S. For example, at Schneider, all the new trucks the company buys have automated transmissions.

According to Bill Collins, owner of Interstate Truck Driving School in South St. Paul, Minnesota, "the kicker for driving instructors is increased safety." He explained to the Star-Tribune, "Most of my students want to drive the manual and I try to talk them out of it. The biggest reason is the safety [of the trucks with automatic transmissions]."

Collins stated that there is less for drivers to worry about when they don't have to shift gears. But because some companies still use trucks with manual transmissions (because they don't replace trucks as often as the big over-the-road carriers), Collins still teaches students to drive a truck equipped with a manual transmission.

One of Collins counterparts, Gary Pressley, president of Heavy Metal Truck Training in Eagan, Minnesota, predicted, "In the next three to five years, pretty much everything is going to be automatic," when he was interviewed by the Star-Tribune.

Real-life results

Sean Kilcarr, a writer for American Trucker, spoke with John Kingsley, a former owner-operator turned company driver with 22 years of over-the-road experience, for an article he wrote in February 2018.

Kingsley has split his career between flatbed and dry van operations. With that experience, he knows how to shift gears to get the best possible fuel economy, a skill he built on millions of miles of hard-won experience.

In Kilcarr's article, he chronicled how Kingsley test drove a 2018 model Freightliner Cascadia equipped with a 15-liter Detroit engine mated to a 12-speed DT12 AMT. In the American Trucker article, Kingsley explained, "Overall, the truck continues to amaze me with its ability to handle shifting under just about every situation thrown at it," following a two-week test run.

"The predictive cruise control, which uses a database of terrain mapping to adjust the speed of the truck as it crests a hill, and then allow it to coast as needed down the backside, works wonderfully in most situations," Kingsley said.

But, he told Kilcarr, "It does, however, require you to actively keep abreast of the speed going downhill on extended grades. In my truck's settings, it will allow itself to exceed my company's preset-governed limit by 5 mph before auto­matically applying the Jake brakes to slow the truck. Under conditions where the truck's roll-out would exceed our governed speed, I do have to apply the [engine brake] manually to keep it within the set guidelines."

From the vantage point of many fleets, another aspect of the transmission that Kingsley learned was its impact on fuel economy. After two weeks and over 7,300 miles, Kingsley reported that his AMT-equipped 2018 Cascadia averaged 8.4 mpg, even with engine idle time included.

Fuel savings like those are another reason fleets – and many owner-operators – are shifting to AMTs. Another reason is that AMTs decrease driver fatigue, explained Gedert. "AMTs… are absolutely a benefit from a driver fatigue perspective because the transmission does the work for you and eliminates the need to repeatedly use a clutch for manually shifting gears."

Kurt Swihart, marketing director for Kenworth Truck Co. told American Trucker, "As drivers age, reflexes slow down, joints get stiffer and muscles weaken. Arthritis, which is common among older adults, can make it harder and often downright painful to shift gears, particularly after a full day of driving," he explained. "Then there's the traffic in and around metropolitan areas. Over the years traffic conditions there have become increasingly difficult and taxing on even the best drivers."

Peterbilt's Slavin pointed out that both fleets and owner-operators will continue to move toward AMTs and fully automatic gearboxes as a way to improve both driver retention and recruitment efforts. "Driver retention is crucial as the driver workforce pool ages," he stressed.

The ease of driving a truck with a fully automatic gearbox or AMT provides a more comfortable environment for "tenured" drivers, while they make training new drivers easier. "As younger, less experienced drivers are entering the workforce, the growth of AMTs and automatic transmissions increases," Slavin noted.

But it's the fuel efficiency benefits that are key, explained Scott Kuelber, general manager of Detroit component sales. He told American Trucker, "What AMTs do is bring your worst driver's performance closer to your best driver. AMTs… don't have bad days. They can skip shift to get to top gear as efficiently as possible and ensure that you’re always in the most optimal gear. Cruise control usage plays a major role in fuel efficiency and, while in cruise, AMTs can leverage ‘predictive’ technologies to use the truck's kinetic energy to limit fueling, shifting and braking."

Costs of AMTs and automatics

"Those worried about the higher price of an AMT should consider the benefits, like improved fuel economy, safety, reduced maintenance, [longer] clutch life, and the opportunity for a lower cruise speed rpm," Gedert said. "These [AMT] transmissions will more than pay for themselves."

So how much more does an AMT or a fully automatic gearbox cost versus a manual shifter?

American Trucker reported that global consulting firm Frost & Sullivan conducted a study in 2017 to answer that question for several different commercial truck segments and to identify some of the "ripple effects" from broader AMT adoption. Among the company's findings, according to American Trucker:

The medium-duty truck premium for AMTs averages $600 to $3,000 per gearbox, increasing to between $1,000 and $5,000 for heavy-duty units.

The medium-duty truck premium for fully automatic transmissions averages $3,000 to $6,000 per gearbox, rising to between $6,000 and $10,000 for heavy-duty units.

With newer dual clutch automated transmissions (DCTs), the medium-duty premium averages $3,000 to $5,000 per gearbox, while the heavy-duty premium averages between $5,000 and $10,000.

According to the study, the high initial costs compared with the potential to gain fuel savings is the primary factor currently inhibiting mass adoption of all three types of gearboxes, which Frost & Sullivan term "electronically controlled transmissions," or ECTs.

Frost & Sullivan also reported that worldwide in the next decade, AMTs are expected to have a compound average growth rate (CAGR) of 12.5 percent, while fully automatic gearboxes will experience a CAGR of 7.7 percent.

The firm pointed out that manual transmissions will decline in the global heavy-duty truck market from a market share of 81.4 percent to 65.5 percent by 2025.

"As drivers age, reflexes slow down, joints get stiffer and muscles weaken," Kurt Swihart, marketing director for Kenworth Truck Co., told American Trucker., "Arthritis, which is common among older adults, can make it harder and often downright painful to shift gears, particularly after a full day of driving," he explained. "Then there's the traffic in and around metropolitan areas. Over the years traffic conditions there have become increasingly difficult and taxing on even the best drivers."

Where do we go from here?

In North America, Frost & Sullivan predicts the market share for manual transmissions among medium- and heavy-duty trucks will decline to 43.5 percent by 2025, while the AMT market share will grow to 29.4 percent, with fully automatic gearboxes at 27.1 percent.

The takeaway? Manual transmissions will remain a market leader for the foreseeable future; however, their market share will continue to decline. A combination of younger drivers with little or no experience with manual transmissions, safety considerations and fuel economy will feed the decline. But there will always be those who would rather depress the clutch and shift the gears.

Keep on truckin’ and keep grinding those gears!

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