Re-think How You Spec Your Dump Truck

Aftermarket emissions devices and electronic engine technology are changing the way dump trucks are spec'd.

Changes made over the last few years to meet EPA emissions regulations will have a notable effect on the way you spec your next dump truck.
Changes made over the last few years to meet EPA emissions regulations will have a notable effect on the way you spec your next dump truck.

Many of you may not have purchased a dump truck since before the 2007 EPA emissions regulations were implemented. In 2010, even more stringent emissions regulations required yet another technological leap. “Trucks have changed drastically over the past years,” says Martin White, director of vocational sales for Navistar. “New engines are quieter and more efficient.”

Exhaust gas circulation (EGR) and selective catalytic reduction (SCR) aftertreatment are now common, yet are still misunderstood. “A lot of guys don’t even know what that is about,” says Alan Fennimore, vocational marketing manager, Kenworth Trucks. But you must understand emissions technologies and how they impact frame spacing and other specs. If it’s been a while since you spec’d a dump truck, your old specs may no longer work.

“Your dealer salespeople are your best avenue for understanding what specs have changed,” says Fennimore. They can work with you to determine the best solution. There may be trade-offs to consider.

“With the technology changes necessary to meet EPA10, and now OBD13/GHG14 compliance, the powertrain spec process definitely changed,” says Mary Aufdemberg, director of product marketing for Freightliner Trucks. “Freightliner Trucks has several guides that can help you fine-tune the specs to optimize the right powertrain packages for the specific vocational application. We recommend you work with the truck equipment manufacturer and Freightliner Trucks dealer early in the purchasing process to develop a powertrain package that maximizes the return on investment.”

Less Space on Frame Rails

The aftertreatment systems required by 2010 emissions standards take up more room on the frame rails. “With the added componentry required with EPA10, the overall weight of the trucks has increased and the available frame rail space has decreased,” says Aufdemberg.

“This leaves less space for the equipment that is typically packaged on the rails, such as hydraulics, lift axles, toolboxes and other equipment,” says Stu Russoli, construction product marketing manager for Mack Trucks. “The additional aftertreatment can cause additional relocation of components rearward, such as fuel tanks, battery boxes and so on. This can effect the weight distribution of the truck, as well as the wheelbase length. It is critical to know where all the chassis components will be mounted prior to ordering a truck, because this will prevent any surprises when the truck arrives at the body upfitter.”

The space previously used to mount work equipment or lift axles may now be taken up by a chassis component. “Mack provides various aftertreatment and fuel tank packages to help fit all application needs,” says Russoli. But there are trade-offs when saving space. “A 26-in.-diameter fuel tank will have less ground clearance than a 22-in.-diameter fuel tank, and a vertical SCR behind the cab will force the body to be mounted further rearward of the cab. These things need to be considered when ordering a truck.”

Therefore, it’s critical to work with your dealer and truck equipment manufacturer to spec a truck with the most efficient use of frame rail space.

Mid-chassis packaging is crucial to having a clean and timely body upfit. “The DEF tank size and location is an important part of mid-chassis packaging,” says Aufdemberg. “Other components that have an impact on body upfit are exhaust configurations, fuel tank location/size, air tank location, battery location, as well as clear PTO openings.”

“DEF tank placement is important to minimize the time and money required in the bodybuilding process,” says Peter Schimunek, marketing segment manager for Western Star Trucks. “The size of the DEF tank is determined by the total fuel capacity on the truck, and the size of the DEF tank determines the placement on the frame rail. Whether working with a dealer or a bodybuilder, request a recommendation on size and placement to help minimize expenses.”

“Generally speaking, for dump trucks and other vocational single fuel tank applications, we recommend mounting the DEF tank integral to the fuel tank,” says Russoli. Mack Engineering designed a fuel tank where the metal skin is extended on one end. The DEF tank is then inserted in this pocket, creating a tighter package that is lighter and takes up less frame space, since no additional mounting brackets are needed to hang the DEF tank.

Choose the Right Powertrain

Fuel economy has also become more important. “Customers are becoming more conscious about their needs when it comes to powertrain selection in the vocational market,” says Schimunek. “While it might make sense to get the biggest, most powerful truck possible, a bigger truck isn’t necessarily the best fit for the job.”

Aside from the upfront cost, consider the cost of insurance, daily operations and maintenance. “Work with a trusted, knowledgeable dealer to ‘right size’ a truck,” Schimunek recommends.

“Customers have definitely become smarter about spec’ing an engine,” says White. “My advice is to evaluate the mission required for the truck and make sure startability and reserve horsepower at cruising speed requirements are met by using the appropriate gear ratio.”

There are no clear-cut solutions that apply to every application. “It is really hard to say which powertrain package will maximize ROI due to the vast differences in applications and needs,” says Russoli. “There has been an even split in MP7 (11-liter) and MP8 (13-liter) engine use in Mack Granite models. The lighter MP7 engine can generate up to 405 hp at 1,480 lbs.-ft. torque, which makes it a great option for the fuel- and weight-conscious customer. This is not to say that using an MP8 means these customers are overpowered. It may just show that some applications require more power than others or the power benefit outweighs the cost savings.”

Engine technology has changed a lot in the last five to six years, with significant changes in horsepower and torque curves. “People have definitely seen that a 13-liter built correctly and with the correct power band is able to do the job of the majority of 15-liter engines,” says Fennimore. “We are able to capture 85% of the ratings available in the vocational markets.”

This also allows a significant weight savings. “We are getting around 300 lbs. weight savings with a 13-liter vs. a 15-liter engine,” says Fennimore.

Of course, the regions and application really drive the decision on the appropriate engine size. Mountainous regions or areas with higher weight load limits will still prefer the power provided by the larger displacement engines. In the Northwestern U.S., there are higher payload limits and many contractors use truck and pup combinations. “Guys around here have been using our Paccar MX engine, which came out in early 2010,” says Fennimore.

Get in Gear

The change in engine technology also carries over to the transmission.

“Choosing a transmission for a dump truck is dependent upon the customer’s application,” says Russoli. “The Eaton 8LL and Mack T310MLR (multi-speed reverse) were always the favorites for off-road and creeping applications, but Mack also makes a T313LR and 318LR (low range forward gears) with the ‘low hole.’ The 318LR exceeds all other manual transmission sales in the Granite model. It really allows more flexibility with the low range creep gears and the ability to roll through all the gears when fully loaded or to skip through the gears with lighter loads.”

Kenworth reports that the Eaton 8LL is still the preferred dump truck transmission with its customers. But there are variations depending upon region and driver skill.

For example, in the Northwest, many drivers prefer 18-speed manual transmissions. “The skill level of the driver pool in the Northwest is a lot higher,” says Fennimore. “You can’t just throw anyone in a truck and pup in downtown Seattle. The drivers have to be a lot more skilled and attentive.” In this case, the 18-speed transmission offers more versatility. “You are in the right gear at the right time, especially on steep grades.” But it takes a high skill set to take advantage of this transmission.

Fennimore notes that some customers do spec over the road 10-speed manual transmissions (a ‘10C’ for example), but he personally advises against it. “The ratios are not right,” he says.

Driver retention and driver skill levels are also pushing the industry toward increased use of automated and automatic transmissions. These transmissions can have a major impact on maintenance costs. “The Allison is pretty much a maintenance-free transmission if you don’t overheat it and keep the fluid clean,” says Fennimore.

The automated transmission can extend clutch life. “You could get another 100,000 miles out of your clutch just by having an automated manual,” says Fennimore.

The transmission makes the decision on when and where to shift, which minimizes driver abuse. “As drivers are becoming harder to find, the automated transmission is much more forgiving with the driveline,” says White.

“Automatic transmissions also reduce driver fatigue in high-volume clutching situations, and represent one less thing for the driver to be concerned about on the busy jobsites,” says Russoli.

Freightliner recently held a customer ride and drive event with various vocational trucks (114SD, 122SD) with manual, automated and automatic transmissions. “The overwhelming response was how impressed everyone was with how well the automated and automatic transmissions performed,” says Aufdemberg. “Feedback from participants included that driving a truck with one of these transmissions would really reduce driver fatigue; and it would help drivers better concentrate on operating the vehicle without the stress of making those critical shifts.”

“As newer drivers enter the industry, automatic transmissions are becoming more popular due to reduced training time,” adds Schimunek. “Automatic transmissions may provide increased productivity vs. manual, and provide smooth, effortless shifting in off-highway applications for optimal performance, even when operating in challenging terrain.”

Another factor driving the trend toward automation is efficiency. “Drivetrain components have made huge improvements in the past several years,” notes Aufdemberg. “Advancements in engine and transmission technology make the automated and automatic transmission much more appealing for vocational applications.”

“Automated transmissions can bring other advantages such as improved fuel economy, improved driver efficiency, creep mode, hill hold aid and ease of operation, which allows for a larger pool of drivers,” says Aufdemberg. Automated transmissions are offered in up to 18 speeds, allowing customers to match the transmission to the job.