Test Drive: Kenworth’s Next-Generation T680

The Next Generation Kenworth T680 features a host of upgrades inside and outside the truck to make it safer, more comfortable and more fuel-efficient.

Photo: Jack Roberts

The first time I saw a Kenworth T680 was on the floor of the Mid-America Trucking Show in Louisville, Kentucky, back in 2012. The new T680s were tricked out in a “Lamborghini gold” paint scheme and looked impossibly sleek and modern. Inside were driver-focused cabs and sleepers with an impressive array of new creature comforts and safety-focused vehicle systems, pointing the way toward a whole new era in trucking.

That new era is unquestionably here. If you figure the average Class 8 truck model has about a 20-year shelf life, it’s no surprise Kenworth decided it was time to update the T680 and take advantage of the latest vehicle and powertrain systems available.

I’ve always felt that Kenworth does an exceptionally nice job of blending that old, “classic” American long-nosed truck with the sleek, modern lines required to deliver optimal fuel economy. So if you’re a fan of the T680’s look and stance, there’s no need to panic. Kenworth engineers have taken a fairly restrained approach to the exterior of the new truck, which they’ve officially dubbed the 2021 Next Generation T680. In fact, it takes a fairly practiced eye to pick out of lot of what they’ve done to the hood and fender-lines on the updated model.

In essence, they’ve smoothed out lines and crafted new, cleaner pathways for air to move over the front of the truck and down its sides, thanks to new fairings, an astoundingly low ground clearance, and new fifth-wheel and tandem axle fairings. That’s in addition to a new aerodynamic bumper and hood, turning vanes, durable lower fairing extensions, chassis fairings, wheel-well closeouts, 28-inch side extenders, tandem drive axle fairings, and wheel covers. All of these enhancements are laser-focused on keeping the airflow as close to the truck’s cab as possible to reduce drag-causing turbulence.

All told, according to Jonathan Duncan, Kenworth design director, these subtle changes to the truck’s front profile delivered an impressive 6% fuel economy increase over the previous-generation T680 with a comparably spec’d Paccar MX-13 diesel engine.

Duncan says the new hood on the Next Generation T680 is 8 inches narrower than the previous version of the truck. But unless you have a previous version sitting next to it, that’s not apparent when you’re looking the new T680 over. The overall stance and demeanor of the truck appear virtually unchanged.

A new light package for the Next Generation T680 includes optional LED headlamps and a new, high-visibility turn signal on the trailing edge of the front fenders.

Photo: Jack Roberts

To my eye, the most noticeable new “cool” feature on the truck is narrow, brightly lit, vertical accent lighting on the trailing edge of the front fenders, just ahead of the cab doors. These new lights look sharp while the truck is cruising down the highway. But there’s more to them than just looks: The lights are perfectly situated from a height and blind-spot perspective to serve as highly noticeable turn indicators, designed to give the truck an added measure of safety when changing lanes or turning in heavy traffic situations with lots of four-wheeler passenger vehicles in the mix.

The fenders themselves are lower than on the previous version of the T680, in order to better channel air over and around the steps. And borrowing a little super car technology, there’s also a passive-pressure vent behind the wheel wells to let crosswinds through, lessening lateral forces on the truck as it cruises down the highway.

The chassis fairings have been redesigned to be more aerodynamic – but also much easier to access without tools. A simple, easy-to-find-and-toggle lever actuates a flip-down access panel to the battery compartment. While the fairings seem to ride awfully low, Duncan says they’ve been designed from new composite materials to absorb and deflect impacts from curbs, debris and other road hazards without taking any damage.

Underneath all of this is a much-improved chassis packaging arrangement, Duncan says. This allowed Kenworth engineers to shorten the T680’s wheelbase, providing a smoother ride with fewer vibrations, as well as allowing reduced trailer gaps from 38 to 42 inches. New sleeper side extensions help tame this notoriously difficult aerodynamic area while allowing easy access to the truck’s frame.

Inside the Cab

To get a full, in-depth, feel for everything the Next Generation T680 has to offer, Kenworth flew me out to its headquarters in Renton, Washington, just outside of Seattle, for a briefing and an extended test drive in the new truck.

My test rig for the day was spec’d for serious long-haul work, with a 76-inch high roof sleeper berth in a Deep Cerulean blue paint scheme and the Driver’s Studio sleeper package, which includes amenities such as swiveling passenger seats, dinner table and TV mount, and premium audio system. To say the truck’s interior was plush is an understatement. It featured sumptuous leather seats – “black with Madrona Accents,” according to the spec sheet – and Kenworth’s Diamond VIT top-line interior trim package. In short, the interior looked great and smelled fantastic.

Under the hood sat a 405-hp Paccar MX-13 diesel engine mated to a Paccar 12-speed automated transmission. The truck featured the full suite of Kenworth aerodynamic features and tipping the scales at 67,000 lbs. All in all, a perfectly reasonable example of how this model truck would be fitted out and run in the real world.

Getting into the Next Generation T680’s cab is a safe-snap, thanks to ample, sturdy and ergonomically placed grab-handles both inside and outside of the truck. Once you’re in the seat, the excellent interior layout of seat, steering wheel and mirror controls make quick work of settling in and getting situated for a day out on the road.

Turning the key switch, located to the left of the steering wheel, fired up the big MX-13 up front. It quickly settled into a quiet rumble while it warmed up – an excellent introduction to the serious noise abatement work Kenworth engineers have put into this cab structure to minimize powertrain and road noise.

A quick scan of the dash reveals a somewhat sparse display compared to the busy dashboards of yore with their bank upon bank of dials, gauges and switches. But before you can dwell on the lack of gauges, the new Kenworth 15-inch digital display screen in the center instrument cluster comes brilliantly to life, complemented by the familiar NAV+ infotainment screen located in the center dashboard.

The screen features crisp, vibrant colors and a full suite of easily customizable gauges. An incredible amount of vehicle and situational information can be accessed in an instant with a mere sweep of your eyes. Brian Lindgren, director of research and development at Kenworth, told me there’s been a lot of discussion about the new display screen because it is such a striking departure from traditional truck dashboards. But once drivers got familiar with the screen and how it functions, the feedback has been overwhelmingly positive, he said.

The screen can quickly be set up to display as much – or as little – vehicle information as you desire. A rolling toggle wheel on the steering wheel controls lets you quickly expand or collapse the display screen to your liking with your thumb. In case of a problem, the screen flashes any alerts in a quickly recognizable message, which can then easily be dismissed to cut down on distractions until you’re able to address the matter.

A Technological Tour de Force

Our preplanned route out of Renton took us east toward Maple Valley, Washington, before cutting down to the south and picking up I-405 heading back toward Seattle. It was a nice mix of two-lane backroads, country highways and full-blown Interstates that gave me a chance to experience the Next Generation T680 across its full operational spectrum.

Paccar is clearly sold on the performance and fuel economy of its MX-13 diesel engine. Even with 67,000 lbs. behind it, the 405-hp engine had no trouble getting the rig up to speed quickly, quietly and efficiently. The Paccar 12-speed automated transmission is as solid a gearbox as any heavy-duty truck transmission on the road today. And there’s no question it helps make driving the T680 a much smoother and safer experience, providing silky hands-off shifts at exactly the right times to keep the big truck rolling down the highway.

In fact, taken as a whole, the Next Generation T680 has an almost automotive feel to it at times – as if you’re behind the wheel of a large, luxury, SUV, and not in a Class 8 truck with a loaded 53-foot trailer behind you.

Thanks to the narrow, sharply sloping front hood, views out and around the Next Generation T680 are outstanding. But as we got out of the Seattle traffic and onto a quieter stretch of country roads, I found myself captivated by the 15-inch digital display and the advanced vehicle safety systems Paccar engineers have integrated into it.

The Paccar Automated Transmission featured Predictive Cruise Control with Neutral Coast Capability, the new Lane Keep Assist with Torque Assisted Steering system, and Kenworth’s Lane Departure Warning system, which combats lane drift due to fatigue and distractions. The Kenworth Collision Mitigation system detects when the truck may be about to collide with another vehicle or object, and then alerts and assists the driver by taking pre-emptive braking action, when necessary, to avoid or reduce severity of a collision. The final piece to this new integrated safety system is the Kenworth Side Object Detection system, which continuously monitors the passenger side of the truck, and gives the driver audible and visual alerts when an object or vehicle has entered certain zones.

In this profile shot, you can see the more sculpted, sleeker lines Kenworth engineers gave the Next Generation T680, as well as the tighter trailer gap area, which is now optimized for better fuel economy. 

Photo: Jack Roberts

With all these systems constantly helping the driver keep track of what’s going on around the truck, it feels amazingly safe, even in heavy traffic. Even more remarkable is how efficiently all of the information from these systems is presented to the driver via the new digital display.

It took me about an hour to familiarize myself with the dash screen layout and understand how and where various bits of information were being displayed on it. But once I got the gist of it, I was fascinated by the amount of information readily available to me at a mere glance: The speed of the car in front of you and the closing distance in seconds. The posted speed limit and your pre-set cruise speed. Your lane orientation. Your rpm and the tachometer “sweet spot” for optimal fuel economy. All of that information – and so much more – is all right there for you to access quickly and easily and act upon as needed. And let’s not forget your fuel, DEF, battery, coolant, and other critical information on the truck’s health.

Duncan pointed out a couple of other cool features. The first was the preset speed limiter, which functions as a complementary system to the predictive cruise control. When the cruise control is on, you can quickly use a couple of up/down buttons on the steering wheel to dial in a desired vehicle speed. Once that speed is selected, the transmission will not allow the truck to exceed it, either in cruise control or while you’re actively on the throttle. It’s a great feature for small towns or construction zones, because you can quickly set your top speed, then there’s no worrying about getting a ticket because you got distracted, were moving along with the traffic flow, or simply forgot how fast you were supposed to be going. It’s a great safety tool that delivers peace of mind in potentially tricky traffic situations as well.

The other cool new system on the Next Generation T680 is the Lane Keep Assist with Torque Assisted Steering. This is essentially a smart boost to the truck’s hydraulic power steering system, using electronic control systems to actively adjust steering inputs to counter various driving situations. For example, when you’re at very low speeds or backing up, the system eases torque feedback from the power steering system, allowing faster, more accurate lock-to-lock steering inputs and response. As the truck begins to go faster, the system adds more torque to the steering response, so the driver has a better, tighter, feel for the road and can drive with precision at highway speeds and when changing lanes or tackling long curves.

As slick as this system is, Kenworth has taken things one step further by adding a torque input selector switch, located to the right of the steering wheel on the dashboard. The switch has three settings, which allows drivers to pick a steering feel that’s the most natural for them, from a rather loose low setting up to a significantly stiffer feel in the third position. I tried the system on all three settings, and found them all to be perfectly fine before setting it on the highest position. I’ve always personally like a good, tight-handling vehicle.

The new T680 is definitely a “Next Generation” truck for Kenworth, and one that builds nicely on its existing reputation. The truck is a technological tour de force that offers something for everyone. Fleet owners will love the new aerodynamic package and the fuel economy numbers it delivers. Fleet executives and drivers alike will benefit from a truck that uses technology to make it so much easier to be safe in chaotic road conditions.

Spec Sheet: 2021 Kenworth T680

Configuration: 76” High Roof Sleeper

Engine: Paccar MX-13 diesel

Transmission: Paccar 12-speed Automated Transmission

Front axle: Meritor MFS12E+ 12.5k Std Track

Front suspension: Taperleaf Lightweight 12.5K

Rear axle: Paccar Axle 40K Dual, STD Track

Rear suspension: AG400L 40K Dual 52" AS

Driver assistance features: Predictive Cruise Control/Neutral Coast, NAV+ HD, TruckTech+, Lane Keeping Assist with Torque Assisted Steering