Test Drive: Is International's HX620 the Driver's Vocational Truck?

August 2016, Government Fleet - Test Drives

by Tom Berg - Also by this author

The HX620 has a setback steer axle and 120-inch BBC, and comes only with a Cummins ISX15. Shorter models use Navistar’s own N13 diesel. Note external air cleaners and many other items in chrome or bright metal. Photos: Tom Berg
The HX620 has a setback steer axle and 120-inch BBC, and comes only with a Cummins ISX15. Shorter models use Navistar’s own N13 diesel. Note external air cleaners and many other items in chrome or bright metal. Photos: Tom Berg

Navistar has declared that it wants to build trucks that drivers want to drive. That includes the new HX vocational series, unveiled early this year at an extravaganza in Las Vegas.

I’ve been wanting to drive one since I saw several of the new HXs at that event, which began with a mock televised police chase involving a red dump truck stolen from downtown Vegas. It roared onto a dirt lot near The Strip, followed by the wailing police cruisers. The truck drifted right and left as it entered the lot, then ran around the area several times before black-and-white cruisers surrounded it and cops arrested the suspects.

Drifting in the dirt was not in the script, an insider said later, but you couldn’t blame the guy behind the wheel. Like I said, this is meant to be a driver’s truck and he drove it.

That red dump truck is the very truck you see here, according to Chad Semler, HX product marketing manager. He was my guide at the Navistar Proving Grounds in northern Indiana, west of South Bend.

You can bet that I didn’t do any drifting or anything else overly enthusiastic because we were being observed by the grounds’ chief engineer of operations, Brian Jacquay, who shadowed us in a Ford SuperDuty pickup with a Navistar-built V-8 diesel. He clearly was serious about safety. Besides, many years ago I learned respect for equipment and don’t like to beat on trucks. I followed Semler’s directions as I steered the HX over a gravel trail and pavement with rumble strips and other rough surface features.

One is an “undulating” asphalt course originally laid out by engineers from Studebaker Corp., the car and truck maker that established the track in 1926. Early last year, Navistar bought the 675-acre facility from Bosch, its most recent owner, and has moved formal course testing formerly done at the old technical center in Fort Wayne to this sprawling complex. It’s only a 90-minute drive from the company’s headquarters in Lisle, west of Chicago, and not much farther from the engine works at Melrose Park, Ill.

While most truck builders like to spotlight their own diesels, Navistar is perfectly fine with featuring a Cummins diesel, in this case a 14.9-liter Cummins ISX15. Renewed availability of 15-liter power (after previous Navistar management banished it from the International lineup) enabled a re-entry into the “premium” vocational market, current executives have said. The return of Cummins diesels and use of its exhaust aftertreatment systems for Navistar engines has helped the truck maker increase truck sales, cut deep losses and return to modest profitability.

Better financial performance also gave the company the means to buy the proving grounds. The huge facility is a profit center for Navistar, and fully 70% of the testing here is classified as “outside,” Jacquay said. That includes military contracts and operations by component suppliers and other truck builders. 

The HX620 and another long-hooded model in the HX series use the big Cummins. With a 500-hp rating, this engine was way more than adequate to propel the truck and its load of about 10,000 pounds of gravel. The engine ran through an 18-speed automated Eaton UltraShift Plus, which handled much of the work of driving the truck. I noticed that the UltraShift let the engine rev to 1,900 and 2,000 rpm in the lower gears, so I used the up arrow on the selector pad to prompt earlier upshifts. Semler explained that the transmission was programmed for vocational duties, and most customers prefer higher revs for better performance over rough terrain and while climbing grades.

The Cummins ISX15-500 had way more than adequate power for our test. The long hood is needed to house the big-block diesel, but is easy to open and close.
The Cummins ISX15-500 had way more than adequate power for our test. The long hood is needed to house the big-block diesel, but is easy to open and close.

A quick explanation of the labels: HX means “Heavy eXtreme,” for the anticipated duties the vehicles will see. The “6” in this truck’s designation means a setback steer axle, and the “20” denotes a 120-inch bumper-to-back-of-cab measurement. The other ISX15-powered model is the HX520, with the same BBC but a set-forward steer axle, indicated by the “5.” Their long hoods are needed to accommodate the big-block engine. Two shorter-hooded models are the HX615, with a setback axle and 115-inch BBC, and the HX515, with the same BBC and a set-forward axle. Both use Navistar’s 12.4-liter N13 diesel.

Basic styling for all HXs is big and bold, with a large nose similar to the recently departed Cat Truck, which was built for Caterpillar by Navistar using the International PayStar as the starting point. (Semler said no one at Navistar knew that Cat planned to cancel its CT series, and “we learned about it at the same time everyone else did.”)

The HX, too, is based on the PayStar, and will replace that venerable model, which will soon be phased out. Even with their roomy aluminum cabs, PayStars I’ve driven in the past have been bare-bones trucks, and I’ll bet drivers of dumps, mixers and other heavy work trucks will be happy to see the nicer HXs show up in their fleets. Semler said the first HX delivered to a customer went to a logger in British Columbia, Canada.

The chassis includes 12-inch-high by ½-inch thick main rails with 3¾-inch webs, which is stiffer than many frames using reinforcements, he noted. One Cat Truck feature used in the HX is the combination speedometer and tachometer. Navistar also used a similar two-panel wrap-around dashboard, as well as an overall upscale theme.

This HX620 was very nicely appointed, with chrome and other polished-metal pieces brightening up the exterior. Inside it had a deluxe trim package that included leather-covered seats, brightly rimmed gauges and attractive paneling on doors, walls and ceiling. A simpler package is also available.

A comfortable interior includes nicely trimmed instruments,  rich-looking door and wall panels, and leather-covered seats. The big circular speedometer-tachometer is easy to read. Buttons on  the keypad to the driver’s right control the Eaton automated 18-speed.
A comfortable interior includes nicely trimmed instruments,  rich-looking door and wall panels, and leather-covered seats. The big circular speedometer-tachometer is easy to read. Buttons on  the keypad to the driver’s right control the Eaton automated 18-speed.

Noise was well dampened, especially during loops around the 3-mile oval track where we cruised at 65 and 70 mph, and even as we banged and bounced over the endurance courses. Air-ride seats and twin airbags at the cab’s rear corners insulated us from much of the jolting. Wiring was not the Diamond Logic multiplex system but a less complex “point-to-point” setup, Semler said. 

You’d expect a setback steer axle to allow good maneuverability, and the one on this HX620 did. Wheels cut by up to 40 degrees in left and right turns, even with wide 425-series tires supporting its 20,000-pound rating. This means the truck can ably move through sharp corners and around obstacles on job sites.

The tandem drive axles rode on a Hendrickson HaulMaxx mechanical suspension, which is standard on the HX; the ride was acceptable, but probably would’ve been better with one of the air-rides available. A single pusher axle added capacity to the 10-wheeler; this “tri-axle” configuration is the norm in Indiana, Pennsylvania, Alabama and certain other states.

This driving experience was shorter than others I’ve done, but covered a variety of terrain and showed what the HX is capable of. I saw solid, agile handling, good maneuverability, decent comfort and ride quality, and commendable quietness. And that big hood is very easy to open and close, thanks to long shock-type supports, and a triangular rib on top serves as an aiming stake to line up the truck with the right edges of the pavement.

Premium is as premium does, and it appears that International has done things right with its HX series.



International HX620, conventional-cab vocational straight truck, aluminum cab, Metton hood, BBC 120 in., w/ 12 x 3¾ x ½-in. main frame rails & 150,000-lb. front tow pin


Cummins ISX15, 14.9 liters (912 cu. in.), 500 hp @ 1,800 rpm, 1,650 lb-ft @ 1,200 rpm, w/ engine brake


Eaton UltraShift Plus FO-18E318B-VXP (Vocational Extreme Performance) automated 18-speed double overdrive

Front axle

20,000-lb. Meritor FMS-20-133A w/ Sheppard M100/M80 dual steering, on 20,000-lb. parabolic leafs & shock absorbers

Lift axle

20,000-lb. Watson & Chalin SL2065 Tru-Track steerable pusher

Rear axles

46,000-lb. Meritor RT-46-160P w/ 4.10 ratio, on 46,000-lb. Hendrickson HMX 460-54 mechanical


232 in.


Meritor Q-Plus S-cam w/ Bendix ABS

Tires & wheels

425/65R22.5 Continental 465 front, 11R22.5 Continental 491 rear, on polished aluminum discs

Fuel tank

Single 100-gal. 26-in. diameter polished aluminum


22-yd. Ox 19-ft. smooth-side Ultra-Lite steel dump

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