DENVER, Col. – The demise of Sterling and GM’s withdrawal from the medium-duty truck market created a gaping void in the Class 4/5 arena; a void that Navistar International hopes to fill with its new International TerraStar.

“We’re the market leader in the medium-duty segment and the main way for us to sell more product is to enter into different markets,” Navistar International’s Paul Schunke said during a recent media ride and drive event. “OEMs are exiting the market and customers were asking us for a more commercial-grade vehicle and that’s why we got into that (Class 4/5) market.”

With their departure, GM and Sterling abandoned about 26% of the market, a significant share that Navistar wasn’t willing to leave to the incumbent players.

Navistar’s answer to the more heavy-duty requirements of the light-duty commercial vehicle segment is the International TerraStar, a Class 4/5 offering that delivers commercial-duty functionality in a smaller package for a wide range of applications. It goes head to head with the remaining players in this thin segment, namely Ford and Dodge, which offer the F-450/F-550 and Dodge 4500/5500 respectively. (Hino has also come out with a new Model 198 for Class 5 applications).

Because of its strong presence in the Classes 5-7 markets, Navistar was able to bring a new model to market quickly by borrowing heavily from existing products. The cab was taken from the DuraStar, the front and rear axles and brakes from the CityStar. The truck is powered by International’s new MaxxForce 7 engine with 300 hp and 660 lb.-ft. of torque.

“To start from scratch, with a new cab, new frame and new suspension – that’s a multi-year program,” Schunke said. “We had this big tool shed from which we could bring all these tools, which allowed us to significantly cut down development time.”

New to the TerraStar is the frame, which is lowered six inches compared to the DuraStar, making it easier to climb into and out of the cab. Since International is no stranger to designing and building work trucks, most of the worker-friendly attributes came as no surprise. For instance, the grab handles are big enough to grab hold of while wearing work gloves, I noticed while driving the TerraStar on a road course laid out by Navistar during a test drive at Denver’s Invesco Field.

About 70% of the medium-duty trucks built by International today are matched with Allison automatic transmissions, which make the truck remarkably easy to drive and also optimize fuel efficiency. This is important, since these trucks are often operated by workers who have received no formal training on fuel-efficient driving.

The TerraStar I drove had the standard Allison 1000 Series automatic transmission, which the company says optimizes power output as well.

The truck drove much like an oversized pick-up truck, which will be an easy adjustment for workers who may not have experience driving commercial vehicles. Because the TerraStar uses the same spacious cab as its bigger brother the DuraStar, the cab is available in a variety of configurations including a 26-inch extended cab and 44-inch crew cab.

When it comes to medium-duty applications, visibility is important. Not only because inexperienced drivers may often be behind the wheel, but also because in many cases, the truck will be operated in cramped work sites.

The TerraStar offers excellent visibility all-around, thanks to the elevated seating position in the supersized cab. This should help owners cut down on repair costs. Equally important when it comes to avoiding dings and scrapes, is turning radius.

The TerraStar falls just short of its competitors in this category, with a 28.2-ft. left-hand curb-to-curb turning radius (compared to 26.4-ft. for Ford and 27.3-ft. for Dodge). But Tom Schmitt, sales training project manager with Navistar, says turning radius is a subjective metric.

“Actual turning radius is going to depend on the axle, the tires, the steering gear and everything else you have under the front end of that truck,” he said.

The course I drove included some tight right- and left-hand turns, which I navigated without crumpling so much as a single pylon. Granted, before I pat myself on the back too enthusiastically, I should note the course was built wide enough to accommodate the bigger DuraStar as well. At any rate, when the difference in turning radius is measured in inches, it’s not likely to be a deal-breaker.

Another strength of the TerraStar is its serviceability, which should really come as no surprise since the truck borrows from the best of International’s proven medium-duty models.

The TerraStar has a tilt hood, as any serious work truck should, rather than the alligator-style hood opening you’ll find on the Ford or Dodge offerings.

Schunke said serviceability seems to have been an afterthought in the Class 4/5 market, something International intends to change. In some cases, the entire cab had to be lifted off the frames of competitive vehicles to perform engine maintenance. The TerraStar’s engine can be easily accessed from either side, making it simple to perform everyday inspections and replenish fluids.

Speaking of fluids, you won’t find a diesel exhaust fluid (DEF) tank on the TerraStar. While Ford, Dodge and Hino have elected to meet stringent EPA-mandated NOx emissions standards with exhaust aftertreatment, the International MaxxForce 7 instead eliminates NOx in-cylinder.

That means customers won’t require DEF for the selective catalytic reduction (SCR) system used by all other medium- and heavy-duty truck manufacturers in North America. While a compelling argument can be made for and against SCR, it’s one more differentiator that Navistar feels will work in its favour.

The International TerraStar is a true commercial-grade Class 4/5 that borrows heavily from the company’s proven medium-duty products. The large cab and big truck appearance do come at a premium though. It’s expected the TerraStar will cost more than its Ford and Dodge competitors to the tune of a few thousand dollars.

Nonetheless, interest in the truck seems strong. By last October when I drove the truck, Navistar officials said they’d received orders for about 800 units, generated by trade show appearances alone with no presence yet established on dealer lots. But dealers should have received their TerraStars by now.

In a market segment with few choices, the TerraStar will be a welcomed addition.