Your Guide to the New Class 8 Iron

Jim Park

While we haven’t seen a lot of brand new iron from the OEs this year, we saw two great new trucks from Kenworth and Peterbilt launched at the Mid-America Trucking Show. Later, we heard about Western Star’s 4700 “baby 8”. Then, just after we went to press, Daimler announced their new 2014 Cascadia.

In addition to the new trucks, we now have an expanding lineup of natural gas engines and trucks to put them in. All the OEs have some natural gas option, and a few have a very full plate to offer.

As well as the trucks, there are a few very forward-thinking options now available that will save owners both time and money. Here’s a short list of what has hit the market so far this year, and if it’s a sign of what’s to come, I can hardly wait for the rest of the year to unfold.


The big news from Kenworth so far this year is the T680. Available in day-cab and sleeper options, its newly sculpted hood, cab and sleeper represent what Kenworth claims to be a 10-percent enhancement in aerodynamics, which translates to a five-percent improvement in fuel efficiency.

The design effort of the T680 took Kenworth engineers out to truck stops and other places drivers congregate to see what they wanted in a truck. Item for item and measure for measure, the T680 is the truck 90 percent of the drivers interviewed said they wanted. My test-drive article in the May issue of Today’s Trucking “State of the Art” tells that story, and a ride in the T680 will tell the rest of the story. 


Navistars engineers have been busy making it easier to diagnose faults and get them repaired. The company recently rolled out its OnCommand Connection, a vehicle support program that provides vehicle information while the vehicle is on the road. OnCommand Connection uses truck performance data to proactively interpret and anticipate needed maintenance.

The system works through a device installed in the vehicle that detects engine events and vehicle service requirements through engine performance data within the engine control module. When an alert is detected, a message is sent to the Navistar OnCommand Customer Support Center. Then, an OnCommand Repair Advocate identifies the closest International dealer, confirms the needed parts and tools are available, and contacts the customer to schedule the needed maintenance appointment.

OnCommand Connection is currently being piloted, and will be available standard on model year 2013 International ProStar+ trucks with a free two-year subscription to the service.


Mack trucks, who has long touted its integrated drivetrain, rolled out the Super Econodyne powertrain designed with all-Mack proprietary components. Mack claims the combination of the MP8-445SE engine, mDRIVE automated manual transmission, proprietary C125 drive axles and Mack’s custom software offers up to 3.5-percent better fuel ­efficiency compared to other similarly spec’d vehicles.

Available on all Pinnacle models rated up to 88,000 lb GCWR, Super Econodyne is engineered to “down speed” more than 200 rpm at a highway speed of 65 mph, cruising at 1,160 rpm versus 1380 rpm.

At a press conference at Mid-America, Mack said the Super Econodyne powertrain would not be offered on MP10 engines, but that was prior to Volvo’s XE16 announcement. We’re hoping Mack gets engineering approval to offer a similar package to its heavy-haul customers as well. And more recently, they announced a couple of new natural-gas options.


Western Star

Last spring at the Work Truck Show in Indianapolis, Western Star launched its “baby 8” 4700 model targeted at vocational and municipal customers wanting a midrange powertrain and its somewhat lower cost. It was rolled out in various configurations, but all were straight chassis designs. In early May, Western Star introduced a tractor version of the 4700 model, available with a choice of three power plants: Cummins’ ISC and ISL, and Detroit’s DD13 with ratings from 260 to 450 hp and 660 to 1,650 lb-ft of torque.

Also new to the Western Star stable is the SB4900 FE, and fuel-efficient set-back axle tractor intended for over-the-road operation. There’s also a special package for weight sensitive applications that includes light-weight components such as aluminum clutch housings, fifth wheel, suspension components, front axles, and air and fuel tanks.


Building on last fall’s release of its low-rpm XE13 powertrain package, Volvo announced at Truck World the availability of the two new XE16 packages. Each package features a new D16 engine rating of 500 horsepower and 2,050 lb-ft. of torque. XE16 improves low-rpm drivability by delivering the full 2,050 lb-ft. of torque while running as low as 1,000 rpm. Developed for gross combination weights up to 143,000 pounds, the heavier-spec XE16 package utilizes heavy-duty, 44,000-lb suspensions and rear axles with a 3.21 ratio instead of the 3.73 rear axle often specified on for LCVs. The XE16 package reduces cruising rpm from 1,425 to 1,225 at 100 km/h, yielding about a three-­percent fuel efficiency improvement.

The second XE16 rating addresses 80,000-pound tractor and semi-trailer combinations that are spec’d with a focus on both fuel efficiency and high performance. The engine, in combination with a 2.64 rear axle ratio and overdrive I-Shift transmission, will operate within its sweet spot throughout the vehicle speed range to improve fuel efficiency for this class of vehicle.

Volvo also plans to launch a 13-litre liquefied natural gas engine for North America in 2014.


Peterbilt launched its Model 579 at the Mid-America Trucking Show in March. It features a mid-sized cab in a highly aerodynamic package that’s going to appeal big time to drivers who want a larger cab than the 379, but not one quite as big as the Model 587. The truck features distinctive aerodynamic styling and a long list of driver comfort and productivity enhancements.

Jim Park

Jim Park was a CDL driver and owner-operator from 1978 until 1998, when he began his second career as a trucking journalist. During that career transition, he hosted an overnight radio show on a Hamilton, Ontario radio station and later went on to anchor the trucking news in SiriusXM's Road Dog Trucking channel. Jim is a regular contributor to Today's Trucking and, and produces Focus On and On the Spot test drive videos.