Drive: 2003 Dodge Ram Heavy Duty
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Though Dodge rolled out the all-new Ram light-duty trucks last year, those vehicles were saddled with the company's 4.7-liter overhead cam and 5.9-liter overhead valve engines. Truck enthusiasts have had to wait until the introduction of the 2003 Dodge Ram Heavy Duty models to get their first glimpse of the long-rumored 5.7-liter Hemi engine. It has been worth the wait.
On paper, the Hemi looks like a winner, and the good news is that it delivers on that promise. The twin spark plug design lets the engine idle as low as 500 RPM when stopped with the transmission in drive. This condition causes the old engines to sputter and shake, but it remains difficult to tell the Hemi is even running.
Release the brake and floor the accelerator and the good news continues. The 345 peak horsepower and 375 lb.-ft. peak torque sound good, but just as importantly, the low-end torque curve never dips below that of the old 5.9-liter engine. That makes launches easy even while towing heavy trailers. Back-to-back drives with the 6.0-liter Chevrolet Silverado showed that the Hemi matches the Chevy in seat-of-the-pants power and smoothness.
Dodge engineers hushed the Hemi's mechanical clatter and intake honk, leaving more decibels available for the exhaust. The result is a pleasing rumble that enthusiasts will love, but that is quiet enough that passers-by won't notice if they don't want to.
There are still no announcements regarding wider use of the Hemi engine, but Dodge officials confirmed that the new engine plant's capacity won't be taxed by the 25 percent of Ram Heavy Duty trucks powered by gas engines. The 8.0-liter V-10 gas engine is carried over as the maximum-power gas engine available in the Ram.
Which brings us to the new 5.9-liter, 305-horsepower, 555 lb.-ft. Cummins turbodiesel that motivates 75 percent of heavy-duty Ram trucks. The new high output engine manages impressive power that permits a 23,000 pound GCWR (that is truck, trailer and cargo) towing capacity. We tested the Cummins matched with the new six-speed manual transmission while pulling a flatbed gooseneck trailer loaded with a Ford extended cab heavy-duty truck, and found acceleration to be excellent.
The six-speed gearbox shifts easily, and getting the truck and trailer underway smoothly required no special effort or clutch-slipping, despite the heavy trailer. The new Cummins engine is significantly quieter, slashing 8 decibels (that's an 80 percent reduction in sound pressure) from the old engine's racket at idle, and running 6 db quieter at highway speed. The engine's diesel sound and character remain intact, but that character is no longer intrusive.
Do-it-yourselfers will appreciate the 15,000-mile oil change interval, doubled from the previous 7,500 miles. The oil that comes out should be significantly less foul, because Cummins has reduced the particulate blow-by that turns oil inky black. A 250-horsepower, 460 lb.-ft. version of the engine is also available, for drivers who don't need the extra towing capacity of the high-output engine.
The heavy-duty trucks look the same as the light-duty versions, but for the bigger standard 17-inch wheels and tires. The two-wheel-drive models feature rack and pinion steering - a first among heavy-duty models -- while the four-bys have a new low-friction steering box for their recirculating ball steering that gives better on-center feel and feedback than the old truck's steering.
The Ram's frame is fully boxed, front to rear, for maximum rigidity, and is hydro-formed of thicker steel than the light-duty trucks. The two-wheel-drive trucks receive a new independent front suspension, and the four-wheel-drive model, which accounts for 70 percent of heavy-duty Ram sales, has a new front axle. Standard rear axle ratio is 3.73, and a 4.10 is available optionally. Rear leaf springs are three inches longer for a more compliant ride.
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