Transmissions: Automatics, AMTs Offer Fuel Savings, Lower Maintenance Costs, Fleets Say

By Mindy Long, Special to Transport Topics

This story appears in the Dec. 8 print edition of Transport Topics.

Automatic and automated manual transmissions originally gained popularity in this decade as a driver-recruiting tool. Many manufacturers and fleets said they offered the additional benefits of increased fuel economy and lower maintenance costs.

Rising pump prices in recent years have led fleets to try to capture even slight efficiency gains. Automated manual transmission manufacturer Eaton Corp. has sold more than 150,000 units in North America, and spokesman Don Alles said AMTs are improving fuel efficiency for many users.

“Fleets have reported back to us on fuel economy gains as much as a mile and a half per gallon improvement,” he said. “Even for someone who realizes a 1% improvement in fuel mileage, it can bring his fleet back hundreds of thousands of dollars in fuel savings.”

Mike Hasinec, vice president of maintenance systems/support for Penske Truck Leasing Co., said, “In many cases, with a larger fleet, you could easily see a 7% to 10% fuel economy increase. That doesn’t mean everyone is going to get that, but conceptually, it is possible.”

Quantifying fuel economy gains can be difficult because of the variables involved; the largest variable is driver behavior.

“It brings those other drivers that don’t have the expertise of the more tenured drivers up and improves the mpg of the overall fleet,” Hasinec said.

But automatics and AMTs take any guesswork away from the driver.

Mike Pennington, a spokesman for AMT manufacturer ArvinMeritor, said, “The electronically controlled shifting senses load and automatically knows when to skip shifts, maximizing fuel efficiency.”

Ed Saxman, drivetrain product manager for Volvo Trucks North America, told Transport Topics that fleets should examine the quality and experience of their drivers when weighing the benefits of AMTs.

“Automateds could make the worst manual driver drive like the best,” he said, adding, “The amount of influence that a driver has dwarfs those amounts of influence we’re able to achieve with any of the technologies we’re trying to improve.

“The best manual driver in a fleet won’t necessarily see tremendous fuel gains, but the worst will,” he said.

Lou Gilbert, director of North American marketing for automatic transmission manufacturer Allison Transmission, said acceleration and cruising are the main factors affecting fuel consumption.

“The most critical component to achieving maximum fuel economy during cruising is engine [revolutions per minute]. Whether a truck cruises at 10, 40 or 65 mph, having the engine operating in its recommended area is the best way to reduce fuel consumption and increase mpg,” he said.

Full-power shifts also allow fleets to reach higher average speeds, Gilbert said.

“Higher average speeds over a day mean more work is accomplished . . . with proportionately less fuel,” he said.

Hasinec said, “For those drivers that don’t have the experience to shift on a manual, you eliminate things like grinding gears that lead to clutch replacement and new drive shafts. The average clutch in a Class 8 truck from a parts standpoint is around $1,000. That alone can help pay for the added expense upfront.”

Truckload carrier U.S. Xpress Enterprises said it converted its entire fleet to AMTs in 2000.

Marty Fletcher, director of technology and training, equipment research and development, said it is hard to quantify the fuel savings because cleaner-burning engines introduced this decade have decreased fuel economy.

“The question for us is, What would the fuel economy have been without the AMTs?” Fletcher said. “I have seen people who came out of a manual take one of these, and their fuel efficiency improved significantly.”

John Kreilkamp, president of Kreilcamp Trucking Inc., uses automatics on nearly all of his fleet of 350 trucks. He began using them in 2001 to attract drivers and said they have made a slight improvement in fuel economy, as well as reduced maintenance costs.

“You’re not putting in clutches like you would if you had a manual transmission,” he said.

Fletcher said that, while the number of broken internal transmission parts decreased dramatically for U.S. Xpress, another variable was introduced because failures can occur in the electronic components.

“Those types of repairs were possibly as frequent but weren’t as expensive,” he said.

However, not all companies that have used AMTs have been able to improve maintenance or fuel mileage.

For example, Con-way Truckload has 63 AMTs in its fleet of 2,792 company-operated trucks, said Bruce Stockton, vice president of maintenance and asset management. That number is down significantly from early in the decade, when the company had more than 1,200 tractors with AMTs.

“We turned away from automated transmissions, due to the number of mechanical breakdowns and added repair, downtime and maintenance expense they added,” Stockton said.

Con-way maintains a small percentage of AMTs for drivers who are trained on autoshift only and to test the fuel mileage.

“We are still trying to prove that the automated transmission e-quipped truck will justify its upcharge through improved fuel mileage,” Stockton said. “Automated transmissions add approximately $5,000 to the cost of a truck. [The return on investment] in fuel would have to be at least one-tenth of a mile per gallon improvement to pay for the upcharge over a four-year life cycle.”

Many in the industry acknowledged the reliability of automatics and AMTs has increased since they were first introduced.

Andy Zehnder, on-highway marketing manager for Kenworth Trucks, said, “The technology and overall reliability has come a long way over the years.”

Said Fletcher: “Over a period of years and several different generations of these transmissions, there have been improvements every single time.”

Hasinec said 5.5% of Penske’s Class 8 fleet of 65,000 is automatics or automateds, a 4.5% increase over the past five years.

“We’re beginning to see more and more fleets request them,” he said.

Volvo manufactures trucks with third-party transmissions and with its own Volvo I-Shift that the company introduced in 2007.

Saxman said demand continues to increase.

“Before I-Shift, we had a percentage in the low teens. Now one-fourth of our trucks have automated transmissions. That is double where we were in about three years,” he said.

Zehnder said, “We have seen a steady increase in demand for automated transmissions over the past three years. This demand stems from the changing makeup of the driver base, fuel economy concerns and ergonomics.”

Safety benefits are also cited as a reason for increased use of AMTs and automatics.

“The real benefit is to take the driver’s mind off of having to decide what gear it should be in and when to shift,” Saxman said.

U.S. Xpress couldn’t provide statistics on safety improvements, but Fletcher said he believes there have been benefits.

“With any automatic or AMT, the driver isn’t concerned with shifting at all. One would have to deduce that it is a safer scenario,” Fletcher said.

Averitt Express is nearly halfway through the process of converting its over-the-road fleet of 1,500 vehicles to automatics.

David Broyles, truckload operations manager, said drivers using the converted vehicles expressed to him they feel safer.

“They don’t have to worry about shifting gears. They can just focus on traffic,” Broyles said.

Like other fleets, Averitt began converting its fleet to autoshifts to attract and retain drivers.

“From what we could see and what the projections were showing, you have so many younger drivers and women who say they wanted an automatic. We’re getting ready to appeal to a wider audience,” Broyles said.

“Overall, our experience has been the reason the I-shift is selling is to help retain good drivers and make bad drivers drive better,” VTNA’s Saxman said.

Fleets and transmission manufacturers both said that the trend toward automatics and AMTs will persist.

“We continue to expect the acceptance of automated transmissions to increase over all the marketplace,” Eaton’s Alles said.