2004.5 - 2007 Ram 5.9L Cummins

For many, the 2004.5-2007 Rams featuring the final iteration of a 5.9L Cummins nestled into the engine bay of a heavy duty Dodge prior to the 6.7 Cummins changeover is truly a relic. Because of this, many of us are opting to keep them on the road as the miles continue to rack up in a silent protest against the latest in vehicle technology.

If you’re the proud owner of one of these “classics,” then you’re in luck because we have a substantial collection of stock replacement and upgraded parts to suit any flavor. But before we get into business, for those with a “2004” we need to first point out how to identify whether you have a “2004” or a “2004.5” as its very important to understand because between this mid-model year, they have different injectors, turbo, exhaust systems, valve bodies, and more. One of the easiest methods is from the factory, a 2004.5 will have a complete 4” diameter exhaust with a catalytic converter at the base of the downpipe. The early 2004 models will have a 3.5” downpipe without a cat and then adapts to a 4” exhaust. Another way to check is to locate the red or silver tag on the driver's side of your block. On a 2004.5 the tag will show a torque rating of 600 or a horsepower rating of 325. 2004's will show a horsepower rating of 305. If you are still unsure, call your local Dodge dealer with the last 8 digits of your VIN and they can clarify it for you.

In terms of performance parts, you’re in luck. The diesel performance industry fully supports these trucks for anything from common fix-it parts such as two piece exhaust manifolds to alleviate the common manifold cracking issue to compound turbos to cure your need for power. Because it impacts trucks within this 2.5 model year spread, there’s a couple additional things worth noting. First, the injectors that came originally in these trucks many times called the “505” injectors due to their original Bosch part number, 0 986 435 505, were updated from their original design. Many times while still within the factory warranty, these trucks were notorious for eating injectors that would cause hard starts, poor fuel economy, a drop in power, white smoke, and so forth. In order to remedy this, Bosch made numerous updates to the injectors to solve the problem, which they did. Further, once the 6.7 Cummins came out, the connector tubes, which connector each injector line to a corresponding injector, were updated. The original 5.9L iterations would internally wear, but the 6.7L versions were built out of a harder metal that could better withstand the high pressures they’re subjected to, thus many choose to use the 6.7 versions, including Ram dealerships themselves.

Ram and Cummins made a big change starting with the 2006 model years with the adoption of a CAN Bus capable ECM, simplistically put, a much smarter version of the previous ECM. Due to this upgrade, available chips and programmers will typically only fit either a 2004.5-2005 versus a 2006-2007 model. For example, the Edge Juice with Attitude will have one part number for the early models and another for the later models. Beyond that, brands such as EFILive only support the later model 5.9’s.

For those of us looking to increase the performance of your Cummins, well, the sky is really the limit. For most, a phased approach works best. For example, you start out with a cold air intake and an exhaust upgrade. Then, its time to add a chip or programmer. After that, it’s a good idea to replace the weak factory lift pump in favor of a higher volume unit. Next up, replace the turbo and while you’re there, might as well upgrade the exhaust manifold. Okay, the old truck is running pretty good now, but the injectors are a little tired, might as well go with a set of 60 or 90HP injectors. At this point, maybe its time to upgrade the CP3 injection pump to better handle the larger displacement injectors. And it just goes from there, and as long as its done mindfully, the results at every phase will deliver a great driving experience.

One thing that a 3rd Gen Ram is not known for is an impeccable ride and tight steering. But that’s okay, as there are countless manufacturers who specialize in making your steering buttery smooth and your suspension capable of handling any task. One of our most popular upgrades to these trucks is to replace the garbage factory steering gear box with a Red-Head replacement. No, these are not just your local auto parts store replacement that only lasts two years, trust us on this one. Or maybe you’re tired of how rough your truck rides but still need it capable of handling your heavy trailer(s). No problem, we’ve got an assortment of brands, such as Carli Suspension, that specialize exactly in this department. How about actually enjoying taking your truck down a rough back road or up in the mountains? From mild to wild, we can help you. And just like with the above performance example, we can help you build your suspension in phases.

Overall, we at Diesel Power Products carry everything you need for your 5.9L including AirDog and FASS Fuel systems, Diamond Eye and MBRP Exhaust Systems, ISSPRO EV2 and Autometer Factory Match Gauges, BD-Power Turbo Upgrades, Dynomite Diesel Injectors, Mag-Hytec Transmission and Differential Covers, Smarty Programmers, Valair and South Bend Clutches, Carli Suspension, Snow Performance Water/Methanol Injection systems and much, MUCH more.

Products in this section are designed to work on 2004.5, 2005, 2006 and 2007 model year Dodge trucks equipped with the 5.9L Cummins unless otherwise noted. But as always, if you have questions on fitment, performance, outcome, never hesitate to give us a call or send an e-mail, we would be happy to assist.

Disclaimer: Diesel Power Products is not affiliated with Cummins or any of its subsidiaries or related companies. Unless a product is specifically identified as a Genuine Cummins product that has not been remanufactured, modified, or refurbished, Cummins makes no representation or warranty about the product and has not authorized, tested, or approved the parts for use in genuine Cummins brand products.