“Sign in, please,” the security guard said. “Who are you here with?” he asked. “Trailer Life,” I answered, looking beyond the gates at the sprawling expanse that is the Chrysler Proving Grounds in Chelsea, Michigan.
“There’s a guy here from Trailer Life,” the security guard said into his walkie-talkie. The unidentified voice on the other end squawked a garbled message, and the guard looked up at me. “Get in the black van.”
The black van? I was beginning to feel like I was being escorted onto the grounds of the White House. But this was, after all, DaimlerChrysler’s own backyard, and I was here to see and drive the new Heavy Duty Dodge Rams for the first time.
All-New Chassis
Inside a tent, far removed from the main entrance, attendees were treated to a walk-around of an HD truck chassis. Steve Kenner, director of Chassis Engineering, Truck Platform, explained that the frames for the 2500 and 3500 Dodge Rams are completely new and unique to the Ram Heavy Duty. While they feature hydroformed box sections like those used on the 1500-Series trucks introduced earlier this year, the Heavy Duty frames use thicker-gauge steel construction, and the sections are larger. The new box-section chassis is far stiffer than on the previous-generation Ram, which contributes to improved steering and handling precision, according to Kenner. In addition, the hydroformed box sections simplify the frame-manufacturing process and reduce the number of welds. This improves dimensional integrity and durability by limiting variations in the manufacturing process.
Two-wheel-drive (2WD) trucks feature a new short- and long-arm independent front suspension with gas-charged shock absorbers and stabilizer bar, as well as rack-and-pinion steering, a first in the heavy-duty truck segment. Four-wheel-drive (4WD) trucks receive an improved recirculating ball steering system with a tight, 13.4:1 steering ratio (2.75 turns lock-to-lock) and a refined version of the five-link, coil-spring suspension beam-axle arrangement used in previous heavy-duty models. Two new transfer cases, a conventional manual shift and a new electronic shift are available on 2500 and 3500 4WD models, and are designed to provide quieter operation.
Common to both 2WD and 4WD models is leaf-spring rear suspension with three-inch longer springs and all-new rear axles, which contribute to a segment-leading 12,500-pound gross vehicle weight rating (gvwr). 2500-series trucks receive two-stage leaf springs and 10.5-inch ring gear in the differential, while 3500-series trucks get beefier three-stage springs and an even larger 11.5-inch ring gear. The standard axle ratio is 3.73:1, but a 4:10:1 axle is available and carries with it an additional 2,000 pounds of towing capacity. A new limited-slip differential features a helical gear design and provides torque biasing with little degradation in performance over the vehicle’s lifetime, according to Kenner. The system does not chatter like friction-plate based designs can, and requires no lubricant additives.
Four-wheel disc brakes with huge 13.9-inch rotors, anti-lock braking system (ABS) and Electronic Variable Brake Proportioning (for improved front-to-rear braking balance when the truck is loaded) and 17-inch wheels round out the chassis improvements.
New Cummins Diesel
When the reins of the presentation were handed over to Dennis Hurst, executive engineer of midrange engineering for Cummins, the room fell silent as he began talking about the all-new engines.
Since our first report on the new diesels in the June issue of Trailer Life (see “Power Struggle”), we had heard that the new engine’s common-rail fuel injection and pilot injection would make the clattering Cummins quieter. To some, this would be a blessing; to others, it would be akin to cutting Samson’s curly locks — the Cummins just wouldn’t have that strong personality anymore. Thankfully, Hurst and the rest of the crew at Cummins and DaimlerChrysler did some research before introducing the new engine, and found that most people liked the way the engine sounded, but wished it could be quieter at idle. “We conducted what we called the ‘Wendy’s Test,'” Hurst said. “We kept making the idle quieter until the lady at the Wendy’s drive-through didn’t tell us to shut the engine off (before ordering).”
The result is an engine that is 80 percent quieter at idle than the old engine — a fact that was demonstrated for us underneath the tent when the old Cummins and new Cummins were started back to back. But as quiet as the new engine is, it hasn’t lost any of its character; it still sounds like the old engine, but with the volume-knob turned way down. As such, Cummins seems to have satisfied everyone — the new engine still has the Cummins sound diesel aficionados love, but will also satisfy those who want a quieter engine.
Now for the really good part: The new High Output Cummins Turbo Diesel engine (H.O.) produces 305 hp at 2,900 rpm and 555 lb-ft of torque at 1,400 rpm, which gives it a towing capacity of up to 16,300 pounds, and a gross combination weight rating (gcwr) of up to 23,000 pounds (depending on model and equipment). The standard Cummins engine makes 250 hp at 2,900 rpm (up from 235 hp at 2,700 rpm) and 460 lb-ft at 1,400 rpm. According to Hurst, maximum torque for these new common-rail injected Cummins engines occurs 400 rpm lower than GM’s Duramax diesel V-8, 100 rpm lower than the current Ford Power Stroke, and 600 rpm lower than the Super 600 diesel V-8 Ford will introduce in mid ’03. In addition, the new Cummins has 30-40 percent fewer parts than typical V-8 diesels, has reduced wait-to-start and cold cranking times and features an increased oil-change interval (from 7,500 to 15,000 miles), according to Hurst.
Our brief drive of a new Cummins H.O.-equipped 3500 series dualie was with a large gooseneck flatbed trailer in tow, and a Ford Super Duty F-350 crew cab dually 4×4 parked on it for good measure. While we did not have the opportunity to weigh this rig, we do know that the Ford’s base weight is more than 6,600 pounds, and it’s safe to assume that the trailer weighed at least that much, so it represented a fairly good load for the truck.
On a loop through the suburbs near Chelsea, it was easy to forget the trailer was back there. The truck pulled the load easily, accelerated more than satisfactorily, and could cruise on the freeway at 65 mph in overdrive without the engine lugging. At cruise, the cabin is very quiet, with only a hint of the Cummins clattering away a few feet in front of your knees.
As with previous models, the H.O. Cummins is backed by the NV6500 six-speed manual transmission — at least in the early production trucks. Word has it that there is an automatic transmission in the works that is designed to hold up behind the H.O., but DaimlerChrysler representatives were tight-lipped on the details. In any case, look for automatic-backed H.O. trucks by early 2003.
Return of the Hemi
The 5.7-liter Hemi engine, which produces an impressive 345 hp at 5,400 rpm and 375 lb-ft of torque at 4,200 rpm, is the most powerful standard engine available in a heavy-duty truck — and is also reported to be more fuel-efficient than the 5.9-liter engine it replaces. The new Hemi is backed by a standard NV4500 five-speed manual transmission, or the new 545RFE five-speed automatic, which features three planetary gear sets, one over-running clutch and full electronic control, including the torque-converter clutch.
The Hemi name is legendary, and while DaimlerChrysler maintains it isn’t dwelling on the design’s illustrious history, it certainly isn’t ignoring it. The word “Hemi” is displayed prominently on the front fenders, and engineers saw to it that the engine had an appropriately muscular exhaust note. It sounds good — especially when you mash the throttle into passing gear on the freeway and listen to mechanical music as the tach sweeps into the 5,000 rpm zone. As the power/torque figures would suggest, this engine doesn’t feel like it has a whole lot of pull down low, but in the mid range, its acceleration is impressive indeed. The new transmission’s super-low 3.00:1 first gear should get a trailer moving easily, and the tall .067:1 fifth gear would suggest decent mileage. Overall, the transmission seemed well-matched to the engine’s power band, and shifted smoothly.
Design Elements
As you’ve undoubtedly noticed by these and other photos you may have seen, the new HD trucks look very similar to the 1500 series trucks introduced earlier in the year; that is to say their appearance cues are not drastically different than the previous generation’s. However, there are a number of changes worth mentioning.
The popular Quad Cab (more than 85 percent of Dodge heavy-duty trucks sold are Quad Cab models) features three additional inches of cab space, made possible by reducing bed length from 6 feet 6 inches to 6 feet 3 inches. The same dimensions were carried over to the regular-cab model, and both models continue to offer an eight-foot bed option. Moreover, the cab design of the HD trucks allows for decreased build complexity by combining all designs on just two wheelbases (from as many as 10 on the revious-generation Ram 2500/3500). The long-bed regular cab and short-bed Quad Cab share the same 140.5-inch wheelbase, while the long-bed Quad Cab rides on a wheelbase of 160.5 inches.
Both regular and Quad Cab 3500-series trucks (including the shortbed Quad Cab short bed) are available with a single rear-wheel version, which provides an intermediate step in payload capacity between the 2500 series and 3500 series with dual rear wheels, according to Dodge. Other additions include the availability of power adjustable pedals (in both manual and automatic transmission-equipped trucks), and available side-curtain air bags.
The many changes in the Dodge HD lineup should make the new trucks more valuable to RVers than ever before. Look for a full test of the HD Dodge Ram truck in a future issue of Trailer Life.
