GARLAND, Tex. – We’re on a simulated job site in a new dump truck and Bill McNeilly, chief engineer for severe service products at International Truck Group’s technical center in Fort Wayne, Ind., is offering me some running advice:

“Okay, here come the moguls, so you want to slow down a bit … Now you should make this U-turn if you start turning now … well, that’s not bad – most guys have to make at least one back-up…”

McNeilly, a Canadian who’s also worked for Western Star and its Orion Bus subsidiary, says he worked his way through college in the mid-1950s as an owner-operator dump trucker. He bought a used ’52 Ford F8 and ran it past a half-million miles. Its flathead V-8 engine got rebuilt three times, he once replaced part of a driveline right on a work site, and … Well, the ol’ F8 was a good truck, but almost a half-century of engineering advancements will let this International 7500 with its HT530 diesel go a lot farther with less work.

The new 7000 Series vocational trucks comprise the medium-heavy side of the new “high performance” series launched almost a year ago with the new 4000 midrange trucks. The 4000s have been selling well and International hopes the new models will do well, too, or at least as well as can be expected given the shrunken marketplace.

Helping will be a healthy market for municipal vehicles, according to one study, which also notes that sales to construction fleets are not down nearly as much as those to freight haulers. This is good news for the 7000s, which replace the old severe-service 2000 series and the heavier 4800 and 4900.

They will be built in a remodeled plant in Garland, Tex., just outside Dallas. It’s where Marmons (remember them?) and the old 2000s were once bolted together.

On the off-road course I drove two vehicles available at the Texas intro: the 7500 10-wheel dump that McNeilly coached me in, and a 7400 dump set up with municipal specs. On that ride my guide was Mike Roeth, director of the severe service product center in Fort Wayne. He just hung on, as his seat was solid-mounted, unlike the air-ride seat that gave McNeilly more freedom to talk.

Gravel moguls and a few bulldozed holes showed off suspension articulation and ride quality, while tight corners marked by orange cones highlighted the trucks ability to turn sharply. I noticed the 7500 with its Hendrickson air-ride tandem suspension rode more smoothly on pavement, while the single-rear-axle 7400 was better through the rougher stuff.

Both cabs have air-ride rear mounts, with a pair of air bags and shock absorbers. A similar system was a US$600 option on the old 2000s, but making it standard on all 7000s and 8000s lowers the per-unit cost and gives everyone its benefits. Drivers will like the noticeably smoother ride and lack of cab shake, while owners should see fewer bills for repairs to cab parts.

The steel cab common to all next-generation models is 82 inches wide – enough for three-across seating – and has considerable shoulder, belly and head room. A tilting (but not telescoping) steering column is standard. The steering wheel has wide, contoured spokes with push-button switches for the electric and air horns (hey, where’d the roof-mounted lanyard go?), and for cruise control, if it’s ordered. You can also get power windows and door locks with remote keyless entry.

The 7400 had a flat-across instrument panel and the 7500 had the optional wing type. Gauges, switches and controls are easy to see and use. Gauges are big and nice-looking, and are all-electronic. But the panel is a one-piece unit and if one gauge breaks, the whole panel has to be replaced. Light switches are rockers mounted low and to the left of the steering wheel, as on a car or light truck. Windshield wipers are actuated by a twist ring on the turn signal stalk – the same type used by Ford in its light and medium trucks and by Sterling in its mediums and heavies.

A doghouse covers the rear of the engine, but isn’t wide enough to crowd your right foot. Engineers say they took special pains to insulate and seal the cover to keep noise and fumes out of the cab. The muffler is under the cab and the exhaust stack is mounted to the frame, not on the cab, to keep vibration outside.

With high-capacity front axles – the 7500 had a 20,000-lber -Sheppard dual power steering is standard. Just crank’er and the wheels turn sharply thanks to wide-track axles. Both the 7400 the 7500 trucks negotiated corners very nicely.

The frame has main rails deep enough that most applications won’t need reinforcements, says David Hillman, sales manager for vocational trucks. This cuts weight and cost, and eliminates the potential for corrosion between rails and inserts. But if you need’em, reinforcements are available.

Frames are kept as clean as possible so bodies can be installed without moving chassis equipment. People at the plant say the supplier will pre-punch the rails for a body’s mounts if specs are included in an order. Body wiring plugs into an electrical box under the driver’s door, and air lines can hook into special ports under the cab.

The shift levers on both trucks were free and smooth, though the 7400 had an Allison MD automatic, which seemed to linger too long in the lower gears.

The 7500s are powered by International’s 8.7-liter HT530, with 280 to 340 horsepower and torque of 950 to 1,200 pounds-feet. The 7400 gets International’s bullet-proof DT466, which is also used in most 4000 models. In April, look for a new, smaller V-8 diesel, the 6-liter DT365, to replace the current T444E 7.3-liter V-8. The new 365 will be smaller, lighter and more fuel efficient, but make more power and torque. It will go in an International 4200.

As with the 444, the biggest customer for the 365 will be Ford. It’ll replace what it calls the 7.3 PowerStroke and use the new 365 in heavy pickups, SUVs and vans, and probably some midrange trucks. There’ll also be a 4.5-liter DT275 V-6 diesel for Ford’s light-duty trucks and SUVs.

Mechanics and owners should like the fact that many components in the new Internationals are installed to be easily accessible. And like the new 4000, the 7000 series gets multiplexed wiring that claims to cut wire bulk and weight by as much as 40 per cent. It also simplifies hooking up of switches and speeds troubleshooting.

Sharp styling is the trucks’ most visible feature. It centers on the bold, chromey grille – a bright departure from the painted metal on old models.