Family Addition

Steve Sturgess | July 01, 2012

Ambient red mood lighting adds to the presence of the interior and the new, wider seats offer additional driver comfort.

Kenworth likes the bottom-hinged accelerator pedal, which always makes it a little difficult to place the right foot when using cruise control. Also, the brake pedal sits very close beside the accelerator. But these are small quibbles.

The sleeper appointments are great and work as well in practice as they promise in theory. One particularly great feature is the door-lock switch on the sleeper control panel — a nice touch that shows the engineers really applied themselves and listened to the drivers as they tried to include every detail. I mean, how often have you tumbled out of the bunk just to check door locks?


The new, wider T680 should prove a very worthy addition to the Kenworth line. It may cannibalize a few sales from its T660 and T700 brothers, but more likely it will acquire new sales from competitive brands that have been introduced more recently than the B-cab T600. And it’s available at the right time to stave off any other new competitors in the pipeline. It is an exceptional new introduction that will be highly popular with drivers and should do well for Kenworth.




The T680 is something new for Kenworth. Instead of using flat aluminum panels, bulkhead-style doors and composite panels for the more complex shapes, the T680 has highly tooled doors and door openings and complex curves in the sheet metal and base cab structure. In developing the design, Kenworth worked with industry giant Magna International, drawing on its expertise in designing and producing the tools that can deep-draw the aluminum into the complex shapes dictated by the 680’s cool styling.

Magna also has industry-leading experience with interior design, mostly on the passenger car side. But the revolutionary interior of the T680 shows evidence of new thinking that maximizes the recreational space available in the cab. As cool as some other interiors look, none comes close to the practicality and space utilization of the integrated T680, though it is essential to specify the swivel passenger seat to gain maximum advantage from the space.



Kenworth T680 Sleeper Test vehicle Specs


Frame: Kenworth steel, 10-5/8 by 5/16 inches, 1,776 pounds RBM

Engine: Cummins ISX 15, 485 hp, 1,650 lb.-ft. torque

Engine brake: Jacobs/Intebrake

Transmission: Eaton Fuller FO16E313A-MHP Ultrashift Plus, 13-speed overdrive

Wheelbase: 229 inches

BBC: 125 inches

Front axle: Dana Spicer E-13221 3.5-inch drop, 13,200 pounds

Suspension: Kenworth AG130 air suspension

Steering: Sheppard HD94

Front brakes: Bendix RSD air discs

Front tires: Michelin XZA3 275/80R22.5

Rear axle: Dana Spicer DSP 41, 40,000 pounds

Suspension: Kenworth AG400L, 40,000-pound air-ride

Ratio: 3.42 to 1

Rear brakes: Bendix RSD air discs

Rear tires: Michelin XDA Energy 275/80R22.5

Wheels: Kenworth 7-spoke hub pilot, outside polished

Fuel tanks: Dual 120-gallon, unpolished

Fifth wheel: Holland FWAAL-17

Seats: Kenworth GT704 HiBack leather passenger on swivel

Interior: Diamond VIT, SlateGray with woodgrain and aluminum

Paint: Spinaker Blue Effect, Imron

Other: heated, motorized mirrors; integral roof fairing, skirts, side extenders; exterior sunvisor; remote keyless entry; AM/FM/CD weatherband radio w/ iPod interface; automatic temperature control HVAC; DPF horizontal opposing SCR; PACCAR 130 amp alternator; Eaton clutch with air-assisted hydraulic pedal; Bendix ABS6 4S/4M anti-lock brake system; stamped aluminum cab with panoramic curved glass windshield.




The new Kenworth T680 is available with the PACCAR MX engine as the standard position, but then there’s the Cummins ISX in its established 15-liter configuration as in the test vehicle. Also released is the 11.9-liter ISX, which Cummins says shares much of the design philosophy of its bigger counterpart. It is, though, quite different in just about every respect.

The 11.9 has seen significant development as a natural gas engine and provides an interesting alternative fuel power unit for the new truck.

For this driving evaluation, we were pleased to see the Cummins ISX at a 485 hp rating. This is a 1,650 lb.-ft. engine, so it offers good performance and excellent fuel economy. Coupled with the 13-speed Ultrashift in this application, it is a very flexible package that should please drivers and owners.

The transmission is an overdrive automated with a top gear ratio of 0.73. With the 22.5-inch Michelin rubber turning 511 revs per mile, the overall gearing gives the truck a tall 1,275 rpm at 60 mph, or 1,380 at 65 mph.

More About: strives to maintain an open forum for reader opinions. Click here to read our comment policy.