Manufactures say automatic transmissions make drivers safer and more productive. Older drivers say they’re a crutch. Who’s right?
Adapting automatic transmissions for use in trucking has proven to be difficult. One reason was the inability of mechanical engines and transmissions to “talk” to one another and ensure optimal vehicle performance across a broad array of applications and road conditions.
Early transmissions had a hard time figuring out what drivers wanted. Complaints concerning both frequent and uneven shifts were common, as were problems with “searching” – when transmissions would struggle in hilly terrain to find and stick with an optimal gear. Other problems along those lines emerged at low speeds – in traffic and while docking.
Manufactures say automatic transmissions make drivers safer and more productive. Older drivers say they’re a crutch. Who’s right?
Even so, AMTs continued to make inroads in trucking. Now, engines and transmissions are sharing more data, so performance issues are getting smoothed out. AMTs now are being spec’d on a significant share of new trucks for reasons including fuel economy and easier driver training – and the trend is likely to continue.
Two types of automatic transmissions are available for heavy-duty trucks: Automated manual transmissions and automatic transmissions. Both are two-pedal designs, and most drivers probably would be hard-pressed to tell much of a difference between them in real-world driving situations.
True automatic transmissions feature fluid drive and a torque convertor. Adherents argue they provide 100 percent power and double rim pull, making them ideal for vocational applications.
The basic difference is that automated manuals are manual gearboxes, with all the clutch actuation and gearshifts handled by electronically controlled systems. True automatic transmissions feature planetary gearing with disc packs for clutches and torque converters.
“In this context, an automatic for a Class 8 truck is usually fully automatic, like a typical car transmission, with planetary gearing with several multidisc packs for clutches,” says Ed Saxman, product marketing manager with Volvo Trucks North America. These transmissions have a torque converter to enable powershifts of the planetary epicyclic gearing units that provide the various gear ratios.
An automated manual transmission uses the gearbox of a manual transmission and shifts it by computer, using a computer-operated single large-diameter disc clutch, otherwise similar to a manual clutch.
Mack Trucks says the take rate for its mDrive AMT is currently in the neighborhood of 38 percent, which aligns with other OEMs that report figures ranging from 35 percent to the low 40-percent range.
Allison Transmission’s automatic is designed with the company’s Continuous Power Technology, meaning it never interrupts torque and power to the wheels, says Steve Spurlin, executive director of international application engineering and vehicle integration. “It also uses a torque converter as the starting device,” he says.
An automated manual has incorporated electronic controls with basic manual transmission architecture to facilitate automated shifting of the gears and the input clutch-starting device. Both the automated manual and the basic manual interrupt power and torque every time a shift is made, whether automated or manually, Spurlin says.
According to Steve Rutherford, powertrain marketing manager for Caterpillar OEM Solutions Group, the advantages of a pure automatic design are a perfect fit for the company’s vocational truck line – although he points out that both types of transmissions work well in specific applications.
“Both types of transmissions have two pedals and a shift pad instead of a gearshift lever,” Rutherford says. “It took a lot of work to perfect automated manuals to engage a dry clutch and generate well-synchronized shifts. What they’ve done with those products is amazing.”
But many drivers – primarily older ones – feel that automatic transmissions somehow detract from a skill set they’ve honed over decades. “I’m a truck driver, not a steering wheel holder,” says Carl Ciprian, a driver with Fayette, Ala.-based N&N Transport. Ciprian never has driven an AMT and says he never will, preferring to stick with an Eaton-Fuller 18-speed manual gearbox.
Several OEMS have developed integrated powertrains that share proprietary information between the engine and transmission to deliver optimal fuel economy consistently.
“I can understand why fleets like AMTs,” he says. “It’s all about fuel economy. You know – ‘Instead of teaching new drivers how to drive, just give them all an automatic transmission, and turn them loose on the highway.’ ”
Ciprian, however, sees truck driving as a skill – one in which a truck driver needs to be engaged to do it properly. “Changing gears, and having the additional control over the vehicle that a manual transmission gives you, is an integral part of that,” he says.
But fleets are gravitating toward automatic transmissions – and in surprisingly high numbers. David McKenna, director of powertrain sales for Mack Truck, says the mDrive’s take rate in Pinnacle tractors is currently in the neighborhood of 38 percent, which aligns with other OEMs that report figures ranging from 35 percent to the low 40-percent range.
In some medium-duty applications, AMTs now are spec’d in more than half of new trucks sold. Saxman says that more than 50 percent of all new Volvos sold this year have been spec’d with the company’s I-Shift AMT.
There are several reasons for this significant shift, experts say. Shane Groner, Eaton’s manager of NAFTA product development, says his company’s UltraShift Plus AMT now is enjoying a 25 percent take rate in heavy-duty trucking applications, with on-highway applications logging in at about 15 percent.
“There are still a lot of highly experienced drivers out there who can get the most out of a manual transmission,” Groner says. “Those gearboxes are essentially bulletproof. If you’re a fleet and you’re blessed with an abundance of experienced drivers, and upfront costs are still your primary expense driver, then it’s hard to argue with manual transmissions.”
On the other hand, Groner says, driver skill sets in the industry are changing rapidly. “Many young drivers have never driven even a car with a manual transmission, so they lack even basic familiarity with them,” he says. “The driver demographic is changing. Older drivers are retiring, and they are not being replaced.”
For fleets, though, the appeal of automatics goes far beyond driver preferences, with safety and fuel economy topping the list. “We’ve found that automatics help with driver recruitment and retention,” Spurlin adds. “Automatics allow less-skilled drivers to be very productive. They are also a large help with safety because the drivers can stay focused on the road or the task at hand instead of shifting gears.” Also, drivers do not get as fatigued with an automatic since they do not have to shift gears constantly, he says.
“We have encountered many ‘converts’ – veteran drivers who were once skeptical but now prefer our I-Shift automated manual transmission,” Saxman adds. “Manual transmissions are difficult to ‘skip,’ and most drivers use all 10 gears.”
In contrast, Saxman says, AMTs like the Volvo I-Shift can reach top gear by using just six of 12 available forward ratios. “Fewer interruptions mean faster acceleration,” he says. “As far as fuel efficiency, it is often said that an automated transmission can make the worst driver deliver the same fuel mileage as the best driver, because it’s in the right gear at the right time – all of the time.”
Brad Williamson, powertrain marketing manager for Daimler Trucks North America, says the way fleets spec a drivetrain is changing and that automatic transmissions are a key part of that formula. “The industry at large is now spec’ing lower gear ratios, with direct-drive powertrains becoming more common,” he says.
The concept of “downspeeding” – operating a diesel at lower rpms while at cruise speeds – is being driven by the push for better fuel economy, Williamson says.
“Information is key,” he says. “If you designed both the engine and the transmission, then they can ‘talk’ to one another and share critical information, like what the driver wants, the fuel map, the load, the grade and what the engine is trying to do. The transmission can manage all this information and deliver the best performance possible given all those criteria. A driver just can’t do that consistently. Even if they had all that information, they couldn’t process it and manage the shifts to deliver the same level of performance an automatic transmission can.”
Williamson’s point addresses the latest development in the evolution of automatics in heavy-duty trucking: complete powertrain integration. To date, Volvo, Mack, Daimler and Eaton – via a just-announced partnership with Cummins – all have developed highly integrated powertrains that share unprecedented levels of proprietary information between the engine and transmission to deliver consistently optimal fuel economy at all times.
“It all boils down to the electronics,” McKenna says. “When you have Vendor A supplying an engine and Vendor B supplying a transmission, rarely do those two components share 100 percent of their information 100 percent of the time. Typically, the transmission in those instances ends up making decisions with about 75 percent of the data it needs to make an optimal shift.”
Part 2 of the automatic vs. manual transmission piece will run Tuesday and will cover drivers’ takes on automatic transmissions.
The sibling rivalry between automatic and manual transmissions has raged in the U.S. since automatics were first introduced to the market by General Motors in 1940, and drivers often have strong opinions about which is superior.
At last count, just 3.9 percent of cars sold in U.S. were built with manual transmissions, but in the rest of the world, manual transmissions are still overwhelmingly the top choice. In Europe and Japan, for example, more than 80 percent of cars sold have manual transmissions.
Still, automatic vehicles are becoming more and more ubiquitous in the U.S. Just 30 years ago, 71 percent of vehicles on American roads had automatic transmissions, and today it’s more than 96 percent. Further, Edmunds.com reported that 67 percent of car models manufactured for the 2013 model year were only available with automatic transmissions.
So while die-hard car enthusiasts who love every aspect of driving and people just looking to get from A to B quickly continue to argue over which transmission option is better, we thought we’d offer some updated info about the manual vs. automatic battle and which transmission type wins out in the following three categories:
1: Fuel Economy
When automatic transmissions first came to the market in the 1940s, auto manufacturers selling manual transmissions fought back by touting their vehicles’ superior fuel economy—and they were right. This was due to the heavier weight of automatic transmissions and the inherent drivetrain loss associated, Austin-based mechanic Evan Pokorny says. But, writes Edmunds.com, with the technological advancement of automatic transmissions (namely added gears, which allows the engine to operate closer to its peak efficency longer), the differences in fuel economy are smaller, and in some cases, almost negligible. The manual version of the 2014 Chevrolet Cruz Eco, for example, will save owners about $100 per year over the automatic version—not exactly a windfall. And now in some vehicle models, the automatic transmission actually gets better gas mileage than the manual.
Still, Consumer Reports conducted their own research and found that manual transmissions can, in some models, improve gas mileage by 2 to 5 mpg—a significant difference.
So if it’s fuel economy you’re looking for, you’ll have to compare the automatic and manual version of each year and model you’re interested in.
Verdict: Depends on the model.
2: Performance of Manual vs. Automatic
There was a time, not too long ago, when drivers of serious, high-performance autos wouldn’t dream of choosing an automatic transmission over a manual. The control offered by manual transmissions, the 0-60 acceleration abilities, and the feeling that you’re really driving the car just couldn’t compare to automatics.
With a manual transmission, the driver has greater control: the driver can manipulate the vehicle in interesting ways, like downshifting to slow down, rather than braking. “Manual transmissions are more efficient at allowing more of the engine’s power to reach the drive wheels, which results in faster acceleration in most vehicles,” Pokorny says.
And while sports car enthusiasts in the not-so-distant past might never have considered an automatic, major luxury brands are making the switch. In fact, Ferrari no longer manufactures sports cars with manual transmissions, writes Edmunds. And Fix notes that, “Porsche, Lamborghini, and McLaren all have automatic transmissions in supercars that were once equipped with manual transmissions.” Some of these automakers argue that computer-controlled transmissions can shift faster than any human, actually improving performance. And the semi-manual clutchless shifting many of these vehicles are now outfitted with offers, for many drivers, a good compromise.
But people who truly love to drive—and truly enjoy all of the manual and mental work it entails—still disagree. Ben Stewart at Popular Mechanics writes that, “Shifting a manual transmission is not only more engaging and fun than flicking some dainty little paddles, it also requires more skill and makes the driver a better one.”
For people who enjoy the task of driving, the stick shift still wins out. But when ranked strictly on performance, the type and model (and frankly, the fanciness) of the vehicle now has more to do with the results than the transmission type.
In general, cars with manual transmissions tend to be less expensive—about $8,000-12,000 cheaper, notes Consumer Reports. Shoppers will of course need to compare vehicles on a case-by-case basis, but when looking to save some green, manual is usually still the way to go.
Love to Know adds another wrinkle in the price debate: cars with manual transmissions are on the whole less expensive to repair than cars with automatic transmissions, mostly because automatics are comprised of more complicated technology than manuals. However, as any owner of a manual knows, the clutch will need to be repaired at some point, a fix that usually costs between $500 and $900 dollars. Owners of cars with automatic transmissions won’t need to worry about this particular expense.
They are almost always less expensive both to buy and maintain.
Manuals win. Americans still don’t care.
Manuals win in two of the three comparison categories and tied in the other. So why are manual transmissions on the way out in the U.S. while holding steady in the rest of the world? The answer seems to be a combination of factors: the sheer volume of traffic in the U.S. makes manuals less practical (the stop-and-go of heavy traffic is more laborious when shifting is involved), and automatic cars are seen as (and marketed as) a luxury in the U.S., which means buyers are more attracted to them. But perhaps the biggest factor is the cost of gasoline (or petrol, if you will). Because of government subsidies, the price of gasoline is substantially lower in the U.S. than it is abroad, making small changes in fuel efficiency between transmission types really stand out—a gallon of gas in Europe can cost ten dollars or more, depending on the market.
Yet while manuals may take up a much smaller share of the market in the U.S., Americans do still seek them out. If you’re shopping for a vehicle with a manual transmission, check out Thrillist’s comprehensive and regularly updated list of all cars in the U.S. with manual transmissions.
Julia is a writer living in New York City. She's written hundreds of articles about the auto industry, from demystifying car insurance to exploring the latest vehicle technologies."