Stronger than dirt

June 1, 2010
While construction-truck fleet owners have been hunkered down waiting for the economy to start slipping back into gear or perhaps just for the promised flood of federal stimulus bucks to start flowing their way major changes have been engineered into the powertrains of the trucks they will soon buy. For many fleets, in fact, the new engine and transmission technologies they will encounter when they

While construction-truck fleet owners have been hunkered down waiting for the economy to start slipping back into gear — or perhaps just for the promised flood of federal stimulus bucks to start flowing their way — major changes have been engineered into the powertrains of the trucks they will soon buy.

For many fleets, in fact, the new engine and transmission technologies they will encounter when they next pore over a spec sheet may be very surprising — in a good way. Today's diesels, in particular, may be one or more generations more advanced for plenty of fleets than what they are running now. And fleet owners will find available transmissions, and rears axles, too, that are more advanced than even those on the market a year ago.

Across the board, truck OEMs, engine builders and component manufacturers alike will attest that the powertrain — engine, transmission, and drive axle — is the distinguishing feature of today's construction trucks.

According to these suppliers, the news is all good: Advanced engineering improvements made to powertrain offerings in time for 2010 will ensure that construction trucks will run more efficiently and perform more effectively in the dirt at a lower operating cost — and they will have less impact on the environment as well.

Remarking jovially on how many construction fleets can delay buying new trucks in a down economic cycle, David McKenna, Mack Trucks' director-powertrain sales & marketing, says that “we build trucks that tend to last a long, long time.” But he points out that the OEM is aware of different buying patterns among its customers and the resulting ramifications.

“Some of these [construction] customers buy at least some trucks every year to stay abreast of new technology, while others will only buy trucks as they are needed and so may skip buying trucks altogether for several years.

“And then there are those who run a relatively small fleet and tend to replace the whole fleet on a set schedule, say every five to six years,” he continues. “Now these guys really get the technology changes that come along — and the sticker shock as well.”

McKenna points out that there have been three new engine-emissions rules implemented since 2000 as well as other new technologies, such as roll-stability safety features, smart cruise control and other options, which taken together deliver great benefits but also add cost and complexity to construction trucks now on the market.

McKenna points out that the 2010 EPA-mandated changes mark the “first time a significantly stricter emissions reg has been met and fuel economy has been improved as well. “From '92 on, meeting the regs affected fuel efficiency negatively,” he says. “By '98, we got fuel economy back to where it had been and then 2004 introduced EGR [exhaust gas recirculation] across the board and that was brutal on mpg.”

Fast forward to 2010 and McKenna says it's a whole new ball game, largely thanks to bringing selective catalytic reduction (SCR) aftertreatment technology into play. “Our MP Series engines — 11-, 13- and 16-liter models — for 2010 replace our ASET engines, which were built to meet the earlier emissions rules but off a platform 40 years old.”

The upshot, he says, is the new MP7, MP8 and MP10 engines offer a “significant” improvement, “consuming less fuel and offering longer drain intervals as well as better packaging [within the chassis] and less need for active regeneration for the DPF.” McKenna notes that Mack has distinguished its SCR-based emissions solution by branding it as ClearTech.

“We use no emissions credits on any of our trucks [to EPA-certify them],” says McKenna. “And we continue to see a 5% or more improvement in fuel economy on the road and a boost in the 7% range for typical heavy-duty vocational applications. That's compared to the same trucks powered by 2009 engines.”

McKenna reports that Mack is also up to speed on transmissions for working in the dirt. “We have a series of Maxi-torque transmissions set up to run with our high-torque-rise engines in construction applications. We also offer the T310MLR. It's the perfect, all-around transmission with an extra-low first gear and five shiftable reverse gears to handle getting in and out of job sites.”

He notes Mack also offers Allison 4000 and 4500 Series heavy-duty 5- and 6-spd. automatic transmissions and plans to have available the new 4070 model, which he says is a 7-spd. unit that will boast an extra-low hold in first gear. “That will make it ideal for low-speed operation, such as when a concrete mixer is pouring curbs.”

McKenna says that over the last six years, the spec'ing of Allison automatics in Mack's construction trucks has risen “from the single digits to almost 40%. And that penetration has held steady for the past two years.”

Rounding out the powertrain offerings from Mack, McKenna relates he is “very excited about our new series of rear-axle carriers.” He says the C150/151 is lighter, stronger and stiffer than the previous model and retains Mack's traditional top-load, dual-reduction design. It comes with a standard power divider, a differential lock, and ratios from 3.11 down to 5.66, he added, to provide wide application coverage.


A customer who was not in the equipment market and missed the rollout of the EPA '07 engines will now be buying a better engine, to be honest,” says Jim Zito, Peterbilt's vocational products manager.

“That's because using SCR after-treatment on our EPA '10 Paccar MX and Cummins ISX engines allows us to take the EGR load off the engine a bit, so they run better,” he continues. “And with these engines, the need for active regeneration cycles [to clear the DPF] are cut in half from '07 engines. Those older engines had no SCR to help handle the NOx.”

Zito points out that a much greater choice in transmissions is afforded to construction truck buyers this year. “We offer everything from Allison 3000 and 4000 Series automatics to a full lineup of Eaton Fuller manuals as well as the new Eaton UltraShift automated-manual transmission.”

Zito expects Pete will offer the new Allison 4070 automatic by year's end. He says this transmission has “more horsepower and torque especially when used with a Cummins ISX rated up to 1,850 lbs.-ft. torque. It will be a high-end unit and will put Allison into a niche they have not played in before now.” He adds that he views spec'ing the 4070 and ISX as an “engine/transmission package” that delivers effective torque management.


Zito says there are no rear-axle “breakthroughs” on the vocational side right now, but “there are more people looking at more efficient suspension designs. Instead of spec'ing a spring unit, they may opt for an articulated or air-ride suspension to get more life out of the truck.”

He notes that more construction fleets are looking at placing disc brakes “all the way around,” and sees that as part of a general trend of buyers tending to “look at the truck as a whole package, paying close attention especially to anything they can spec to improve safety and performance.”

Zito points out, too, that Pete is now offering factory-built, all-wheel-drive (AWD) on its medium-duty Model 337, making it “suitable for use as off-road dumps, cranes and utility trucks.” He adds that the heavy-duty Model 365 mixer chassis version has “all the options needed to make a bridge-formula truck.”

Tim Shick, director of marketing for Navistar International's engine business, reports that the OEM's EPA '10 Maxxforce engines deliver higher torque capabilities at lower engine speeds for construction applications. “It's all about peak power at low speeds,” he points out. “That means there's plenty of low-end torque available to deal with difficult terrain at job sites.”

Shick points out that Navistar has a complete line of Maxxforce engines available for all its construction truck offerings, from midrange to heavy-hauler units. Besides their torque characteristics, he says these engines are distinguished by the low noise levels they produce.

“The Maxxforce 11 and 13 are exceedingly quiet engines,” he continues. “This helps cut down driver fatigue and also reduces the [ambient] noise level at job sites for the other workers there. And it's a boon for trucks driving in and out of neighborhoods to access a site.”

As Shick sees it, there are three “big benefits” of the advanced EGR (and non-SCR) engine design Navistar has executed to meet EPA '10 emissions regs:

  • The engines weigh less. “This is key to earth and rock haulers and to cement mixers.”

  • The engines take up less of the valuable space under the hood. “Advanced EGR packaging is the same as for our earlier engines.”

  • The engines do not require DEF (diesel emissions fluid, aka urea). “There is no added responsibility for the driver or the tech.”

He also says the new engines “offer durability without the added weight” of engines with SCR aftertreatment systems. “That's thanks to our use of compacted graphite iron, which is 40% stiffer and has twice the fatigue resistance of gray iron. We use it so the walls of the cylinder liner can be thinned out to reduce weight without giving up strength,” Shick explains. “The upshot is, for example, that our 13-liter engine weighs 2,400 lbs., which is what most traditional 11-liter engines weigh. The 13-liter Maxxforce also boasts 1,700 lbs.-ft. of torque and no [competitive engine] has more torque, and it weighs less than those engines that match its torque performance.”


The adoption rate for automatic and automated manual transmissions has been “growing in the past few years by leaps and bounds in the construction market,” advises Shick. “It's because the capabilities of these units have increased, and electronic integration of the transmission with the engine allows for better shift energy management,” he explains. “This means we can better protect an automatic transmission from the torque put out by diesel engines without needing massive added hardware. Cutting power back electronically during shifts smoothes them out and that protects the transmission and the driveline from shock.”

Because of this, the transmissions last longer in tough service and that holds up their resale value, Shick notes. He adds that automatics and automateds are also drawing buyers because they allow fleets to draw from a wider pool of driver-operators.

According to Brian Daniels, product manager-powertrain for Daimler Trucks North America (DTNA), the two major advantages construction truck buyers will gain from EPA '10 engines will be increased fuel economy and less need for active regeneration cycles for the DPF.

He points out, too, that DTNA has revamped its vocational engine lineup to coincide with the arrival of the 2010 engines. “The Detroit Diesel DD13, DD15 and DD16 products are now available to the construction market. They are replacing the MBE 4000 and Series 60 Detroit Diesel, and are excellent replacements for Caterpillar products, which are no longer available to the market.

“Detroit Diesel's engines offer ratings between 370 to 600 hp. and 1,250 to 2,050 lbs.-ft. of torque,” he continues. “These engines have improved power, performance and serviceability over previous engines.” He notes that DTNA also offers the Cummins ISX as a power choice for construction applications.

Turning to fuel economy, Daniels states that “fleets can expect to see up to 5% better fuel economy over a similarly spec'd EPA 2007 engine. A fleet that switches from an MBE 4000 to a DD13 might see an even greater advantage. Because fuel used in regeneration is a major factor in the 2010 fuel economy improvements, duty cycle will play heavily into the improvements seen by a fleet.”

As for the degree of active regeneration the 2010 engines will require, he says the “overall reduction will be based on operating conditions of the truck. A truck that travels down the road will see more of an improvement in this area than one that idles most of the day.”

Daniels relates that “Freightliner Trucks offers a line of medium- and heavy-duty Allison transmissions, including specific ‘Allison Optimized’ packages. Freightliner Trucks also offers a full line of medium- and heavy-duty Eaton automated manual and manual transmissions.” He adds that Western Star offers heavy-duty Allisons, including ‘Allison Optimized’ packages as well as heavy-duty Eaton automated manual and manual transmissions.

As to rear axle selection, he says that depending on the specific customer's requirements, higher or lower rear axle ratios could be recommended based on improved low-speed maneuverability, fuel economy and desired road speed.


Preston Feight, Kenworth's chief engineer, reports that the OEM's 2010 engine offerings use SCR technology to meet the current emissions requirements and provide customers with increased fuel economy and reliability.

Leading Kenworth's Class 8 engine lineup is the new-for-2010 Paccar MX, which is available with a wide range of 380 to 485 hp. and torque outputs up to 1,750 lbs.-ft. According to Feight, excellent fuel efficiency, low cost of ownership, high reliability and durability, and lightweight design are key features of the MX engine.

Kenworth also has several 2010 Cummins engines in its lineup. The Cummins ISX15 engine, rated from 400 to 600 hp. and 1,450 to 2,050 lbs.-ft. of torque, is offered for the T660, T700, T800, W900 and C500. The Cummins ISL9 engine rated up to 380 hp. and 1,300 lbs.-ft. of torque is available for the Kenworth T440, T470 and W900S. The Cummins ISX11.9 will be available in the second half of 2010 in the T660, T800 and W900S models.

For natural gas vehicles, Feight advises that engine choices include the Cummins Westport ISL G engine at 320 hp. and 1,000 lbs.-ft. of torque for the Kenworth T440 and W900S. The ISL G engine operates on either compressed natural gas (CNG) or liquefied natural gas (LNG). In addition, he notes, the T800 liquefied natural gas truck equipped with the Westport GX engine is rated at 450 hp. and 1,650 lbs.-ft. torque, and up to 1,750 lbs.-ft. if ordered with the Cummins SmartTorque option.

“SCR is the most effective and efficient method to reduce NOx down to allowable emissions levels,” says Feight. “To support the integration of the SCR system, Kenworth offers a wide range of exhaust and DEF tank sizes and locations designed for all customer applications. This means customers can maintain their wheelbase and body configuration when spec'ing Kenworth trucks with 2010 engines.”

“We recognize the emissions impact, particularly on vocational customers where truck frame space is extremely constrained,” says Feight. “We engineered the most advanced DEF tank that provides [a] clear back of cab for these applications. Our 5.6-gal. clear-back-of-cab tank is truly unique in the industry.” He says that when combined with the SCR and DPF of the Paccar MX engines, which are both packaged under the cab access step, there is “essentially no impact to the body builder.” He notes that Kenworth also offers horizontal and vertical independent exhaust configurations on its 2010 model-year trucks.


Transmission choices on KWs include Allison 5- and 6-spd. automatics and Eaton Fuller manual 10-, 11-, 13-, 15- and 18- spd. manual units as well as AutoShift 10- and 18-spd. and UltraShift Plus 13-spd. automated manual units.

The newest offering is the Eaton UltraShift Plus. It is available in 10- to 18-spd. configurations with torque capabilities ranging from 1,450 to 2,050 lbs.-ft. “Fleets are increasingly interested in automated transmissions,” notes Feight. “The unit's new electronic clutch actuation technology will not only benefit our on-highway customers, but also those operating Kenworth T800 and W900 trucks in construction and other vocational applications.”

According to Peter Frantzeskakis, Ford's F-Series engineering manager, 2011-model Ford Super Duty trucks boast an “all-new powertrain” built around the OEM's new Power Stroke 6.7-liter diesel. He says on a single rear wheel (SRW) long-wheelbase truck, the spec improves fuel economy an average of 18% over the previous year's lineup and provides a 14,000-lb. conventional maximum trailer rating.

A Super Duty can also be ordered with an all-new 6.2-liter gas engine that improves fuel economy 15% and is equipped with a new 6-spd. transmission, he notes. The truck also has a new interior with improved climate control, all new seats, and a ‘flow-through console,’ with rear air conditioning on crew cab models. In addition, Ford has retained the 6.8-liter V10 gas engine option for F450 and F550 chassis cab applications.

Frantzeskakis says the 6-spd. transmission on the diesel-powered Super Duty is available with a “Live Drive PTO feature that enables you to operate upfitted equipment like water sprayers, dump bodies and cement mixers.” He notes that a rear electronic differential is offered in a 3.31 and 3.55 ratio for diesel SRW pickups and 3.73 and 4.2 ratios for 6.2-liter gas SRW pickups.

Clearly, there are literally loads of innovation and advanced technology for construction fleet owners to dig through before spec'ing their next purchase of medium- and heavy-duty trucks.

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