The 2004 Dodge Ram 2500 with the 5.7 Hemi uses a five-speed automatic transmission, most commonly the 45RFE. Some late-year builds or specific configurations used the upgraded 545RFE.
To understand the transmission setup for a specific vehicle, it helps to know the typical options Dodge used behind the 5.7 Hemi in this era, how to tell which unit you have, and what maintenance or reliability notes apply. The sections below cover the common choices, how to identify them on your truck, and practical guidance for owners.
Transmission options for the 2004 Ram 2500 5.7 Hemi
Before listing the specific models, note that most 2004 Ram 2500 trucks with the 5.7 Hemi were equipped with a 5-speed automatic, with a second, heavier-duty option appearing in some late builds or particular heavy-duty configurations.
- 45RFE — A five-speed automatic that was the standard pairing for many 2003–2004 gas-powered Rams with the 5.7 Hemi. It is electronically controlled and designed for widespread use in Ram pickups of this era.
- 545RFE — A heavier-duty five-speed automatic that was used on some later or higher-torque configurations within the same generation. This unit offers enhanced robustness for demanding use.
In practice, the majority of 2004 Ram 2500s with the 5.7 Hemi came with the 45RFE, with the 545RFE appearing in a subset of builds intended for heavier workloads.
How to identify which transmission your truck has
- Check the build or VIN data plate, which can indicate the specific transmission model paired with your engine and option level.
- Inspect the transmission pan or the area around the transmission for a Service ID label or stamp that notes “45RFE” or “545RFE.”
- Review the original window sticker or the dealership’s build sheet if available; these documents list the factory transmission code.
- Consult a technician or your local dealer with your VIN to pull a parts or build history that confirms the exact transmission model.
Identifying the correct unit is useful for maintenance, fluid specifications, and potential part compatibility, especially if you’re planning repairs or replacements.
Maintenance and common considerations
Regardless of the exact model, routine maintenance and using the correct fluids are important for longevity. Follow the manufacturer's maintenance schedule and use the fluid type recommended in your owner's manual. If you plan heavy-duty towing or work, discuss with a dealer or transmission specialist whether a specific service interval or upgrade is advisable for your particular build.
Common wear or failure points in these transmissions include fluid degradation, solenoids, and valve body wear, which can affect shifting quality. Regular service intervals and addressing issues early can help extend the life of either the 45RFE or the 545RFE.
Summary
For most 2004 Dodge Ram 2500 models with the 5.7 Hemi, the standard transmission is a five-speed automatic, predominantly the 45RFE, with some late-builds utilizing the 545RFE. To be sure which unit your truck has, check the VIN/build sheet, look for transmission stamps or labels, or consult a dealer. Proper maintenance and using the correct fluids are key to reliable operation.