If you want to know just how fast transmission preferences are shifting in trucking, you need look no further than the Volvo Trucks North America (VTNA) order board. According to Ron Huibers, senior vice president of sales and marketing for VTNA, nearly 40% of all Class 8 orders this year by U.S. fleets are being spec'd with the Volvo I-Shift automated manual transmission (AMT), a 12-spd., single countershaft transmission built up with a splitter, a main section with three forward gears and one reverse gear, as well as a range gear that doesn't require a clutch pedal.

Ed Saxman, drivetrain product manager for VTNA, explains the reason behind that upward swing in AMT selection is simple: It's getting drivers to operate the vehicle in the correct, fuel-sipping way every day, regardless of their experience level.

“One of I-Shift's key advantages is that it makes even drivers with limited experience shift as expertly as the best drivers for improved fuel economy and less stress on the driveline and tires,” Saxman says. “That's another reason why the integration of the engine, transmission and truck with the driver is so important and why so many OEMs are now offering their own proprietary engines and transmissions. It really allows us to bring all this complex technology together in the right way to attain the correct level of emissions, performance, and fuel economy without the driver having to strain to achieve it.”

And it's this change in driver skills that overshadows almost everything in the Class 8 market, says Darry Stuart, president of DWS Fleet Management Services, who spent 30 years of his four-decade career in transportation managing fleets across the trucking spectrum. “The pool of new drivers simply doesn't learn how to shift gears growing up anymore,” he explains. “Consequently, transmissions must be easier to use, more robust, and provide better fuel economy.”

Drawing from his experience, Stuart believes that while the higher sticker price for AMTs and automatic transmissions (coupled with more costly maintenance and downtime considerations) can at times make a wash of fuel savings, their simplicity of operation for the next generation of drivers is a huge advantage.

“It's estimated that upwards of 50 to 60% of the new drivers coming into this industry today don't know how to shift a manual transmission,” he explains. “That has to be weighted against the [AMT and automatic] price premium and maintenance costs, but that lack of shifting ability is a big challenge facing this industry now and in the future.”

SALES SHIFTING UPWARD

Over the last several years, there's been a steady shift among truckers to automated — and now even fully automatic transmissions — for their heavy trucks, says Shane Groner, product planning manager-North America at Eaton Corp. While manuals still maintain market supremacy with an iron fist, their grip is slowly loosening.

Groner says that while sales of AMTs, which are essentially electronically controlled manual transmissions, and automatic transmissions, which utilize a torque converter, won't overtake those of their manual brethren within the next five years, they'll definitely rise to dominate the market within the next 10 to 15 years.

“If you think back 20 to 30 years ago, many people learned to drive with a manual transmission in their family vehicle,” adds Lou Gilbert, director of North American market development for Allison Transmission. “Now, if you would like to purchase a passenger car with a manual transmission, it is an exception or special order. Today, the passenger-car market in North America is nearly exclusively fully automatic transmission based.” Gilbert says the trucking industry is following this trend as well, just 30 years or so later.

“A significant portion of the straight truck and vocational segments are trending toward fully automatic transmissions,” Gilbert notes. “This trend may be the result of the automobile industry not producing many manually equipped vehicles, ultimately reducing the opportunity for drivers to learn the concept of manual shifting. This could also be a contributor to the driver shortage. In either case, it pushes fleet managers to explore easy-to-drive transmission options to attract and retain drivers.”

Right now, Groner explains that it's the cost premium that's preventing many companies from making the shift to AMTs and fully automatic units, noting that an AMT can cost about $2,000 more than a comparable manual 10-spd. transmission. Yet many are also beginning to realize that AMTs — and their fully automatic brethren as well — can save big bucks over their operating life in a variety of ways, offsetting that extra upfront cost.

That's one reason why Freightliner Trucks is highlighting the attributes of its AMT3 transmission, which it says combines the design principles of a manual transmission with what Freightliner calls “intelligent electronics.” This forms an automated two-pedal shift system that equalizes driver performance and improves fuel economy.

Unlike automatic transmissions, the company's AMT3 eliminates the torque converter and instead couples the engine to the transmission with a hydraulically actuated clutch, says T.J. Reed, director of product marketing for Freightliner Trucks. This results in minimal torque interrupt during acceleration and shifting, while providing constant lock-up.

In addition, clutch control and gear shifts are managed by the Transmission Control Unit (TCU), adds Reed. This means that the TCU evaluates road, grade and load conditions to perform shifts at optimal engine rpm, resulting in fast and smooth shifting and significant fuel savings.

“The big value driver is fuel economy,” Eaton's Groner explains. “For example, the software controlling our UltraShift Plus AMT makes every shift just like ones made by the very best drivers in a given fleet, meaning that every truck, not just the ones driven by the most skilled drivers, now has the opportunity to maximize fuel economy.”

A TOTAL PACKAGE

Truck makers themselves are applying this very same logic in terms of how they integrate their own AMT products with their own engines and chassis to create a total system to deliver an improved baseline for fuel economy gains.

“Each engine manufacturer and each engine within each family has a differing fuel-mapping strategy, and this highly guarded proprietary data is not shared completely outside of that engine manufacturer,” explains David McKenna, director of powertrain sales & marketing for Mack Trucks. “Think of this as the recipe for Coca-Cola. You may have an idea, but you simply are not going to get it all. As such, mixed vendor combinations of chassis, engines and transmissions are at a technical and performance disadvantage because the transmission only receives select data.”

So anytime an OEM can get 100% data exchange between all of those components, the ability to manage performance is exponentially increased, including the opportunity to achieve significant fuel-economy gains, McKenna notes.

It's another example of why “integration” and “optimization” are the watchwords governing transmission choice in the future, adds Ramin Younessi, group vice president-product development & strategy for Navistar.

“We've all got new proprietary engines, transmissions and other powertrain components,” Younessi says. “You'll see more integration between the engine, transmission and rear axle as we try to extract a few more percentage points worth of fuel economy out of them.”

Greater integration is also why production of Mack's mDrive AMT, which is Volvo's I-Shift by another name, is being moved to the U.S. starting in the third quarter of 2012. Both Mack's and VTNA's respective in-house AMTs are built by their parent company, AB Volvo, in Köping, Sweden, right now, but production will shift to Volvo's powertrain factory in Hagerstown, MD, with the help of $7 million worth of new investments.

QUICK SELLER

McKenna says that after Mack introduced the mDrive in the first quarter of 2010, it quickly sold out of the 500 units available, mainly because customers could gain up to 1.5% worth of improved fuel efficiency by automating gear shifting.

“The vehicle, engine and transmission share all available data all the time. We can manage shift points based on mass, skip shift as required, and even use the transmission to support engine brake performance by forcing a downshift while maintaining higher engine rpm,” McKenna says in detailing how an AMT like the mDrive can help truckers improve truck performance. “Based upon the vehicle weight/mass, the transmission and engine ECU can even determine which gear to start in.”

McKenna also notes that using an AMT ups the opportunity to revisit what he calls a “new/old concept” of providing constant engine power at extremely low cruise rpm.

“We actually adopted this concept in 1967 with the Maxidyne engine profile, which provided a lot of torque at low engine speeds and constant horsepower from the midrange,” he explains. “With the incredible advancements in air, fuel and combustion management, we can take this idea down to a whole new level, and we may be able to look again at simpler transmissions of five and six speeds via this path.”

These are just some of the advances AMTs can offer truck operators across the board. For instance, Eaton's UltraShift Plus transmissions — both overdrive and direct-drive models — feature a new self-adjusting electronic clutch actuator for fast, smooth engagements that reduce wear and tear on the transmission components, Groner says. There are no more missing gears and burning out of clutches by rookie drivers just learning the ropes.

He adds that intelligent shift selection software employs grade sensing, weight computation and driver throttle commands to make shift decisions for efficient, safe and profitable vehicle performance. Other benefits include:

  • A hill start aid feature prevents rolling while on steep grades and allows for a controlled launch.

  • Automatic, manual and low-mode selections offer control options to the driver.

  • A creep feature significantly improves maneuverability with continuous low-speed control.

  • Six- and eight-bolt, as well as thru-shaft power take-off (PTO) capabilities.

  • An oil level sight glass to easily check fluid levels.

Automatic transmissions are stepping up their game, too, offering their own set of benefits.

“We believe our new TC10 TS automatic for Class 8 tractors will be easier to drive, more capable, more reliable and more profitable for fleets,” says Andy Osterholzer, a member of Allison Transmission's North American marketing team.

Introduced at the 2011 Mid-America Trucking Show, Allison's TC10 is designed to offer what Osterholzer calls “a new approach” to Class 8 tractor transmissions.

The TC10 is an entirely new design of an automatic transmission, possessing a twin countershaft gearbox and full-power shifts via wet clutches and a torque converter, he explains. It is scheduled to appear on the truck market in the fourth quarter of 2012, Osterholzer says.

“The synergy between these components generates benefits and value for our end users,” Osterholzer notes. “Because of the narrow gear steps and full-power shifts, the TC10 will offer superior acceleration, higher productivity, increased fuel efficiency, reduced operating costs, less driveline shock, and smoother shifting relative to both manual transmissions and AMTs.”

The company adds that the TC10 design concept is ideal for distribution applications where a tractor-trailer splits its work cycle between city and highway conditions. Such “full-power shifts” bring productivity and fuel efficiency to stop and go portions of a route, while the 10-spd. countershaft architecture offers fuel economy while cruising, Osterholzer says.

“Initial in-vehicle demonstration tests have allowed us to document some very nice gains in fuel economy and we achieved increases in vehicle miles-per-workday,” Allison's Gilbert adds. “Our testing has shown this new transmission offers better fuel economy than an automated manual in the targeted duty cycle markets for which it was developed.”

THE FUEL GAME

Osterholzer notes that the main driver behind Allison Transmission's entry into the Class 8 segment is fuel economy. “The priority varies by vocation, but it would be difficult to imagine any fleet not interested in saving fuel, relative to its own operating characteristics,” he points out. “High mileage/low specialization applications will value fuel economy more than applications where performance and reliability are absolutely critical.”

However, he stresses that recent third-party survey results have confirmed that fuel economy is secondary to reliability and durability for all applications.

“If the truck is inoperable due to maintenance because it breaks down during operation or it gets stuck in the mud, then fuel economy is not the issue,” Osterholzer explains. “Losing a customer because they can't deliver their service is a much higher concern for most operators. That said, we continue to look at ways to enhance fuel economy, just as we are always looking at ways to improve our product in other aspects.”

Added protection

Two extremely critical factors for new- and used-truck owners alike when it comes to both AMTs and fully automatic transmissions revolve around warranty coverage and service support. Manual transmissions have a long history of demonstrating their ability to handle the punishment dished out by numerous trucking vocations year in and year out. The question is, can their AMT and fully automatic brethren do the same?

Eaton Corp., for one, believes so and is putting its money where its mouth is, so to speak. The company recently added extended protection plans for all makes and models of its UltraShift Plus transmissions in a variety of applications, including standard, linehaul and severe service. Warranty coverage now can cover up to five years or 750,000 mi. Plans can also be purchased within the first three years of ownership.

Allison Transmission has a similar support program in place as well, says Andy Osterholzer, a member of the company's North American marketing team.

“We have 1,100-plus service outlets that are able to perform different levels of service on our product,” he explains. “An owner considering a used truck may want to visit an Allison service outlet to get a ‘Trans-Health’ report on their transmission. This will tell them the current status of transmission clutches and give them a summary of diagnostic trouble codes.

Allison ReTran brand remanufactured transmissions come with a two-year warranty and third year extended transmission coverage is available on the ReTran product when used in refuse applications. Extended warranties, Osterholzer notes, cannot be purchased after the first year of vehicle in-service date.

Defining the terms

Things were a lot simpler when fleets only had to differentiate between manual and automatic transmissions, so here's some clarification of the technology involved:

Manual: A constant mesh transmission with shifting done by the driver through manipulation of the shift lever and foot clutch.

Semi-automated manual: A constant mesh transmission with gear selection done by the driver through manipulation of an electronic shift module. Either pneumatic or electronic systems can be used to move shift forks and rails; a foot clutch is used for starts and stops only.

Automated manual: A constant mesh transmission with gear selection done automatically. Pneumatic or electronic actuators move shift forks and rails, yet no foot clutch is needed. Available in two-pedal (no clutch) or three-pedal format; the latter allows the driver to disengage the automated system and drive manually.

Automatic: Shifts are made via electronic controls. Engine torque is not interrupted during the shift, but is controlled to maintain output torque.