Dodge finds flexibility

Nov. 1, 2007
Dodge has entered Class 4 and 5 of the commercial truck market with the 2008 Ram 4500 and 5500 chassis cabs. It's an exciting new product and an exciting

Dodge has entered Class 4 and 5 of the commercial truck market with the 2008 Ram 4500 and 5500 chassis cabs.

“It's an exciting new product and an exciting new time,” Dodge chassis cab product planning manager Brad Pugh said. “These trucks give us additional upfit flexibility of up to four cab/axle dimensions for regular cabs, going from 60" all the way up to 120". The 4500 has multiple GVWs that go all the way up to 16,500 pounds, and the 5500 goes up to 19,500.”

The new Ram chassis cabs will be offered as dual-rear-wheel modes with a choice of four cab-axle lengths — 60", 84", 108" and 120". The Ram 4500 and 5500 chassis cabs will compete within the Class 4 and 5 segments with a gross vehicle weight range of 14,000 to 19,500 lb. Overall industry forecasts for this range of chassis cab vehicles were 140,000 units in 2006, with growth expectations to 156,000 units by 2012. The Class 4-5 chassis cab segment is expecting further growth to 18% by 2015.

The vehicles are equipped with: the 6.7-liter Cummins turbo diesel, which generates 610 lb-ft of torque; six-speed automatic or manual transmission with power take-off capability; a 52-gallon fuel tank as standard equipment; 390 mm brake rotors; 66 mm caliper pistons; standard diesel exhaust brake system; a frame made of 50,000-psi steel, designed to maximize strength and reduce weight; flat, “clean” frame rails, with industry standard 34" spacing; all chassis components are below the frame surface for easy adaptability and versatility for virtually any upfit application.

The 6.7-liter engine has B5 biodiesel compatibility and reduction in particulates and nitrogen oxide that comply with the 50-state 2007 heavy-duty emission standards. It has life-to-major overhaul intervals of 350,000 miles.

Two-wheel-drive and four-wheel-drive models feature a recirculating ball system that provides precise response and an on-center steering feel through lower internal friction. Improved power steering lines contribute to the delivery of precise feel and response for better handling. Featuring solid-beam front and rear axles, and a five-link, coil-spring front suspension with beam axle, a front and rear link-type sway bar and heavy-duty tubular shock absorbers are standard.

The rear suspension on two- and four-wheel-drive models is equipped with leaf springs and includes standard two-stage springs as part of the spring design for greater load-carrying capability.

Maximum gross vehicle weight rating for 4500 models is 16,500. For 5500 models, the maximum GVWR is 19,500 lb. The GCWR for both 4500 and 5500 models is 26,000 lb.

Bolt-on and riveted-on exhaust hanger brackets provide increased upfitter flexibility, and riveted cross-members behind the cab allow for easier modification. The one-piece C-channel frame, shear plate or U-bolt access along the length of the frame, and shear plate mounting locations identified along the frame contribute to the Ram 4500 and 5500 Chassis Cabs' upfitter friendliness.

The fuel filler is routed through the frame, and an optional mid-ship fuel tank frees up more space behind the rear axle for special upfit applications. Fuel and brake lines are routed together on the frame's left side to make better use of space along the frame, which also has clearance for rear-exhaust routing.

Electrical connections are user-friendly because of three-fused battery feeds routed into the cab and on to the rear of the chassis. A high-current 50-amp ground stud is at the rear of the frame. Upfitter wire circuits and electrical schematics are identified in the body builder guide.

Twin 7"×10" trailer tow mirrors are standard, as are 19.5" wheels. The Ram 4500 and 5500 chassis cabs are available in three trim lines: ST, SLT, and Laramie.

Quad Cab models provide seating for six passengers and are equipped with four standard doors and 60/40 folding rear seat. Seat cushions fold up to create a tall storage area from floor to ceiling. An optional floor section under the back seat folds open to form a flat-load floor with additional storage in each of the foot wells.

Frame changes

Chris Borczon of the Dodge Truck Commercial Vehicle Team said the frame features front tow hooks that are removable for a snowplow; a new front suspension crossmember; new front suspension attachment brackets; new transmission crossmember brackets; and new spring hangers.

“The rear frame rails are essentially the same basic shape and form as on a 3500,” he said. “The holes you see on the 3500 are the exact holes pressed in the same position. The only difference is that the frame is 2 mm thicker. You will want to pay attention on upfits to the front spring hangers. If you have any hardware such as shear plates or horizontal mounting that come close to that stamp bracket, you will want to pay attention to that new large bracket. It has the same footprint, but is a little bigger.”

On dump-body installation on the 4500/5500, he said Dodge's testing has shown that four attachments are required. He also said that exhaust-system modifications require care.

“From the muffler forward, that is an area that can't be modified,” he said. “The particulate trap and regeneration system depend on certain back-pressure numbers. If you modify that, the concern is that you can change the back pressure and get it out of range.

“On the tailpipe in the rear, call us. For simple things such as putting on an exhaust to extend the tailpipe for a wider service body and using the same diameter pipe, that's not an issue. Or if you want to remove the entire tailpipe and put a downturn on it, that's not an issue.”

On PTOs, he said there is the capability to attach direct-mount pumps to the Aisin automatic. The maximum pump size on the Aisin is approximately 11 gpm, though a 4×2 manual transmission can take a larger pump. He said 4×4 manual transmission 4500/5500 models are not PTO-capable.

Dave Donnelly gave an update on retrofitting non-PTO vehicles.

For automatic-transmission vehicles: the vehicle must come equipped with cruise switches in order to have “idle-up” control capability; the patch panel for the floor pan is required and will be available through Mopar (part number 82211579); and the vehicle must be taken to a Dodge dealership and have the “PTO and idle-up” feature enabled.

For manual-transmission vehicles: the vehicle must come equipped with cruise switches in order to have “idle-up” control capability; a clutch up-stop switch is required and will be available through a Dodge dealer (part number 05026273AB); and the vehicle must be taken to a Dodge dealership and have the “PTO and idle-up” feature enabled.

The 4500 and 5500 chassis cabs will be built at Chrysler Group's Saltillo Assembly Plant in Coahuila, Mexico. One of the company's most flexible plants, the Saltillo Plant — which also produces the all-new Dodge Ram 3500 chassis cab, Dodge Ram Mega Cab, Dodge Ram Power Wagon, and Dodge Ram Heavy Duty 2500 and 3500 models — takes on production of the Ram 4500 and 5500 chassis cabs as part of the company's Flexible Manufacturing Strategy (FMS).

The FMS approach allows the company to not only balance production with demand, but to also efficiently build low-volume vehicles that take advantage of market niches, and to quickly shift production volumes between different models within a single plant or among multiple plants.

For production of the Dodge Ram 4500 and 5500 chassis cabs, Chrysler Group recently invested an additional $48 million into the plant, which follows a $210 million investment in 2005 for production of the all-new 2006 Dodge Ram Mega Cab. Enlarging the facility by 120,000 square feet enables the plant to produce commercial vehicles and accommodate new frame configurations. In addition, the expansion increases production capacity and enables the plant to manage the added complexity of the Dodge Ram 4500/5500's all-new commercial-grade chassis and suspensions, including two cab-axle lengths, regular and quad cab versions, 4×2 and 4×4 variants, and single- and dual-rear-wheel models.

Sprinter update

Walther Bloch of the Sprinter engineering and compliance support team said a new generation of regulator is used in the new Sprinter. The alternator regulator is equipped with a Local Interface Network (LIN).

He said the characteristics of the LIN alternators are fixed in the engine-control unit. For this reason, aftermarket alternators can't be retrofitted and a Sprinter should be ordered with the correct alternator from the factory.

The standard equipment for the Sprinter is 180A and an optional 200A alternator (code BAJ) is available. No D+ (engine running positive signal) output is available at the alternator with the LIN bus technology. Only the upfitter connector EK1 under the driver seat should be used.

He said the alternator power supply cable is fused with a 300A fuse integrated in the wiring harness. The fuse location is in the rear of the engine at the bell housing. He said if a short occurs and the fuse blows, then the alternator cable harness has to be completely replaced.

He said that for electrical aftermarket equipment with an amp draw of more than 25A, it is necessary to use the optional auxiliary battery 12V/100Ah lead antimony, deep-cycle strength (option BC1). That option is retrofitable, but for cost and practical reasons Dodge recommends that this option be ordered directly from the plant.

He said that on the Sprinter OM642 diesel engine, it is possible to attach an additional compressor or auxiliary alternator located next to the oil pan. An A/C compressor bracket can be retrofitted by exchanging the existing casting. The compressor pulley and the cooling fan are connected with the crankshaft pulley via a serpentine belt.

About the Author

Rick Weber | Associate Editor

Rick Weber has been an associate editor for Trailer/Body Builders since February 2000. A national award-winning sportswriter, he covered the Miami Dolphins for the Fort Myers News-Press following service with publications in California and Australia. He is a graduate of Penn State University.