{"id":7017,"date":"2024-02-13T20:12:27","date_gmt":"2024-02-13T20:12:27","guid":{"rendered":"https:\/\/www.xtremediesel.com\/blog\/?p=7017"},"modified":"2025-02-18T03:26:47","modified_gmt":"2025-02-18T03:26:47","slug":"2003-2004-dodge-ram-5-9l-diesel-buyers-guide","status":"publish","type":"post","link":"https:\/\/www.xtremediesel.com\/blog\/2024\/02\/13\/2003-2004-dodge-ram-5-9l-diesel-buyers-guide\/","title":{"rendered":"2003-2004 Dodge Ram with 5.9L Cummins Buyer’s Guide"},"content":{"rendered":"\n
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History\/General Info <\/h2>\n\n\n\n

In 2003, the third generation of Cummins diesel-powered Dodge trucks was introduced. The new Ram 2500\/3500 received some major upgrades including new drive-line components, a common-rail fuel injection setup, as well as interior and exterior updates. Dodge continued to incorporate the same recognizable semi-truck styling on the new 3rd gen trucks but made some updates to the grille and headlights for a slightly refreshed and updated look. The interior was also completely revised and featured a host of changes including an all-new dashboard. As the sales battle between manufacturers continued, some major changes were made to the 5.9L Cummins Diesel engine.<\/p>\n\n\n\n

2003-2004 Dodge Ram With 5.9L Cummins<\/a><\/h2>\n\n\n\n

The 24-valve 5.9L Cummins switched from the VP44 injection pump to an electronically controlled common-rail fuel system. This provided more accurate fueling along with improved overall performance and reliability. Upgrading to a common-rail fuel injection system was also key to significantly boosting the horsepower and torque. \u00a0<\/p>\n\n\n\n

The common-rail system utilized a lift pump to send fuel to the Bosch CP3 Injection Pump<\/mark><\/a>. The pressurized fuel was then sent to the \u201ccommon\u201d fuel rail and distributed to electronic injectors. Bosch solenoid-activated electronic fuel injectors<\/mark><\/a> were controlled by the ECM to produce 2 injection events per stroke. These new injectors featured 8-hole nozzles that sprayed at a 143-degree angle.[1]<\/sup><\/p>\n\n\n\n

In addition, the engine block was now cast in a stronger gray iron, with reinforced rails and a stiffener plate to handle the increased power.[2]<\/sup> The engine also retained the same cast-aluminum pistons and forged-steel connecting rods as the prior generation. <\/p>\n\n\n\n

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Bosch CP3 Fuel Injection Pump<\/h2>\n\n\n\n

The Bosch CP3 Fuel Pump is a radial-piston pump comprised of three cam-driven plungers, a high-pressure and low-pressure circuit, a hardened-steel housing and a fuel pressure regulator, also known as a Fuel Control Actuator (FCA)<\/mark><\/a> or Magnetic Proportional Valve (MPROP). The CP3 pump\u2019s primary responsibility was to produce high pressure fuel for the fuel injectors. In addition, the CP3 wasn\u2019t directly involved with controlling injection timing or fuel volume. While it was still driven via the front gear train (1:1 with the crankshaft), the CP3 wasn\u2019t timed to either the crankshaft or camshaft. This was a big change from the VP44 fuel pump found on the 1998.5-2002 engines which was also responsible for pressurizing the fuel, controlling the injection timing, and monitoring fuel flow.<\/p>\n\n\n\n

Horsepower\/Torque <\/h2>\n\n\n\n

In 2003 the Standard Output (S.O.) 5.9L Cummins diesel was rated at 235 hp and 460 lb-ft of torque. The 5.9 High Output (H.O.) Cummins broke the 300 hp barrier for the first time and was now rated at 305 hp and 555 lb-ft of torque. In 2004, the 235 hp engine was reserved only for models sold in California, with the S.O. models now matching the output levels of the 2003 H.O. engine.<\/p>\n\n\n\n

Transmissions <\/h2>\n\n\n\n

For standard output engines, the transmission choices included the standard NV4500 5-speed manual transmission or an optional 47RE<\/mark><\/a> \/ 48RE<\/mark><\/a> 4-speed automatic transmission with overdrive. In models with the high-output engine, the NV5600<\/mark><\/a> 6-speed manual transmission was used (instead of the 5-speed), as well as an available 48RE for those that did not want to row their own gears. <\/p>\n\n\n\n

Chassis & Drivetrain<\/h2>\n\n\n\n

Another big upgrade was a new hydroformed frame with boxed sections. This new frame design helped increase the overall rigidity and contributed to improved steering and handling. In addition, the upgraded frame allowed the new heavy-duty pickups to claim a segment-leading Gross Vehicle Weight Rating (GVWR) of 12,000 pounds.[3]<\/sup> The Dodge Ram Heavy-Duty pickups also featured standard four-wheel disc anti-lock brakes with the largest rotors in the segment. With giant 13.9\u2033 (353mm) front and rear rotors, they were significantly larger than the outgoing 2002 model. These new brakes required a move to larger 17-inch wheels, but significantly helped increase the braking power.<\/p>\n\n\n\n

To further increase driveline durability, new front and rear differentials<\/mark><\/a> were introduced. These differentials were supplied by American Axle & Manufacturing (AAM) and were similar to those found in GM trucks but are typically not interchangeable due to differences in the axle tubes, hubs, and brake\/suspension mounting bracketry. Ram trucks utilized two transfer cases, a conventional manual shift (NV271D<\/mark><\/a>) and an electric shift (NV273D<\/mark><\/a>). The manual transfer case was standard on ST and SLT 4WD models, while the Laramie featured electronic shifting controls.<\/p>\n\n\n\n

What to Look for When Purchasing<\/h2>\n\n\n\n

The 5.9 Cummins diesel is a highly regarded motor and deserves all the praise it receives, but internal engine issues can arise from time to time. Make sure to inspect the vehicle closely before purchasing. Take it for a lengthy drive and get it up to operating temperature. During the test drive pay close attention to the engine and transmission. Make sure the transmission shifts properly and listen for any noises. Furthermore, check for crankcase blow-by; with the engine idling simply take the engine oil cap off and check for excessive fumes. Next, place the cap upside on top of the oil fill opening. The crankcase pressure should not blow it off. If the pressure is too high the oil fill cap will typically blow off. If this is the case, you might want to consider the cost of an engine rebuild when making an offer. <\/p>\n\n\n\n

The common-rail fuel injection system on these trucks can begin to develop issues before the 200K mile mark. If these haven\u2019t been touched in a while, make sure to budget enough money for possible replacement of the injectors or CP3 pump. The lift pump was barely adequate for a stock truck and there is a chance that the CP3 could have been run without proper lubrication (fuel). The front-end suspension and steering components are also prone to wear and tear. Tie rods, ball joints, bushings, as well as the track bar are items that can be commonly worn out and require replacement.    <\/p>\n\n\n\n

Rust<\/h2>\n\n\n\n

As with any older pickup truck rust can be a common issue (depending on your geographic location). Check the rockers, cab corners, bedsides, and wheel well openings for rust or signs of prior rust repair. Inspect for body filler or recent paintwork. Body filler applied directly on rust areas is one way to hide problem areas. This is not an adequate or proper way to repair rust and will not last very long. The frame can also develop varying levels of rust. Closely inspect the frame, particularly where the frame sections are welded together.<\/p>\n\n\n\n

Pros\/Cons <\/h2>\n\n\n\n

Pros<\/strong> <\/p>\n\n\n\n