Quiet and Capable International LT625

Dec. 21, 2016

Before we get behind the wheel of this International LT tractor, let’s see how it fits into the builder’s changing heavy-duty product lineup: Two versions of the LT, for Linehaul Transport, will replace variants of the ProStar, International’s aerodynamic model in production since 2009, as well as the TranStar, a regional-service specialty tractor, that’s being phased out. Also disappearing is the 9900i, the last of the traditionally styled, aluminum-cab 9000 series that dates back into the 1990s and, in Eagle trim, was once the line’s flagship. The unique retro-styled LoneStar, which uses a ProStar steel cab, will carry on as International’s premium model.

Also staying with the steel cab is the vocational WorkStar, familiar as a dump and mixer chassis and heavy plow truck, and medium-duty DuraStar, primarily a delivery truck but also outfitted with heavier chassis, a dump bed, and pavement-clearing equipment for municipal service. Their cabs are getting the Horizon treatment for introduction later this year. The Class 4 and 5 TerraStar is gone, along with its MaxxForce V-8 diesel, and will be replaced with a new model being co-developed with General Motors and due for debut in 2018. The HX premium vocational truck uses an aluminum cab from the 9900i and the PayStar 5000, which is also being discontinued. So the HX is the only model still using the aluminum cab. Got all that?

LT tractors will primarily pull trailers carrying freight over-the-road. But many will haul building supplies and materials for production of concrete and asphalt, among other things, so in that way will also serve the construction industry. The LT is the first model that stems from Navistar’s Project Horizon, a three-year effort to improve steel-cab models. The WorkStar and DuraStar are now being updated for reintroduction later in 2017. The LT name is new, but the truck is based on the ProStar, so it is evolutionary rather than a completely new model.

Goals in designing the LT were improved fuel economy, accomplished through smoother aerodynamics and use of Cummins’ redesigned X15 diesel, and later, Navistar’s own improved N13 diesel. Other goals were more uptime through greater durability and easier servicing of carefully placed components, and improved safety. Navistar is making Bendix’s Wingman Advanced collision mitigation system and electronic stability control standard on the LT to boost safety, executives said at the LT’s unveiling in Las Vegas last fall. Collision mitigation warns of slower objects ahead and will apply the brakes if the driver doesn’t; it has been proven effective in millions of miles of fleet use. Stability control will be mandated by federal rules in about a year, and standardizing on it now gets Navistar ahead of the rule.

The first in the series is the LT625—the “6” for setback steer axle and the “25” for a 125-inch bumper-to-back-of-cab measurement. It uses only Cummins’ X15, the successor to the 14.9-liter ISX15 that has become more popular with International buyers than Navistar’s own heavy-duty MaxxForce diesels. They, and the company, stumbled badly with previous management’s insistence on an all-EGR approach to emissions control. It didn’t work, and revised diesels now use less exhaust-gas recirculation and Cummins urea-injection gear to treat exhaust and break down oxides of nitrogen, an ingredient in smog; the revised diesels carry the N designation. N13 engines will power an LT613 due out in March.

The LT series has more driver “delighter” features: greater comfort and roominess, ergonomically laid out instruments and controls, measurable quietness, better ride, and easier handling, according to the execs. One called it “driver centric.” This is important to recruiting and retaining drivers to counteract the driver shortage that’s a continuing problem for long-haul fleets. So Navistar ran multiple clinics where designers and executives quizzed drivers and fleet owners on what they wanted in a truck and how the ProStar could be improved.

For one thing, the LTs are quiet. That was my initial impression after driving a trio of LT625s around a 3-mile paved track at the Navistar Proving Grounds in Indiana during a special press event. Quietness is engineered into the model, starting with refined aero exterior lines, our hosts emphasized. Noise is kept outside by effective sound-deadening insulation, particularly door sealing. Consequently, wind and road noise are all but gone. That was true for two of the tractors, anyway. The third was plagued by constant squeaks that puzzled me and my Navistar host. Later, reps traced the irksome noise to the hood’s dry rear support pucks. The squeaky pucks received some grease, and the problem was solved, Navistar says.

However, this truck had the sole manual transmission among the trio, and my preoccupation with shifting delayed my noticing the interior noise. The transmission was an Eaton Fuller 18-speed that worked very well with the shift lever and clutch, and was a joy to operate. Out on the track, I slowed several times so I could downshift and go back up the ratio ladder, often using the thumb switch to split the main gears, just for the fun of it. This is seldom the case with manual gearboxes in contemporary heavy trucks, so kudos to Navistar engineers for that.

In the other two tractors, Eaton UltraShift Plus 10-speed automated transmissions worked flawlessly. The tractors’ Cummins X15 diesels were good partners, with strong power and torque unobtrusively interrupted by smooth shifts. A new, compact “column shifter” controls automated transmissions; it was simple and easy to use, with a twist knob at the end of a stalk for choosing Drive, Neutral, or Reverse, and a slide switch for automatic or manual operation. Moving the stalk down or up operates the engine brake or shuts it off.

New interior trim is attractive if muted in color. New instruments have highly legible white-on-black lettering, and switch labels are laser-etched so they won’t wear away as painted lettering does, Navistar says. Controls were all within easy reach, and a glance into roomy sleeper areas showed nicely thought-out storage compartments and comfortable-looking bunks. Integrated sleepers in 56- and 72-inch lengths and four roof heights are available. And of course there’s a nonsleeper day cab. All designs used ideas gathered at focus groups and in conversations with real-life drivers, Navistar executives said in announcing and launching the LT series weeks two before this demo.

Climbing inside to enjoy the interior amenities is rather easy with an LT, which has wide steps and well-placed—for the most part—grab handles. It’s especially easy for the passenger, who has a stout grab handle mounted on the A-pillar. The driver doesn’t and sadly, there’s no option for one—my sole gripe with the LTs that I drove. But the doors’ pockets are strong enough to act as handles, and of course the driver has the steering wheel to grasp while getting in.

Visibility in all directions was good, thanks to the big windshield, large side windows, and effective mirrors, which have been repositioned to reduce the amount of head turn needed to see them. The hood slopes steeply downward and its nose is out of view for shorter drivers like me. Too bad, because the “gun sight” ridge surrounding the orange International diamond nameplate is thus rendered useless, except for its sharp ornamentation. Also unfortunate was my limited time in these pleasurable LTs. Maybe more time will come later.