1. Check the Vehicle Identification Number (VIN):
* Decipher the VIN: The VIN contains information about your vehicle's specifications, including the rear axle. However, you'll need a VIN decoder. Many online resources (some are free, some are paid) can decode a VIN and provide details like axle ratio. Be sure to use a reputable source.
2. Look for a tag on the differential itself:
* Location: The differential is located in the rear of the vehicle, usually under the truck bed. You might need to jack up the rear end for better access.
* Tag Information: Look for a metal tag or sticker directly on the differential housing. This tag will typically list the gear ratio (e.g., 3.55, 3.73, 4.10, etc.) and sometimes other identifying information. You'll need a flashlight and possibly a wrench to clear away any dirt or grime obstructing the tag.
3. Check the owner's manual:
* Specifications Section: Your owner's manual should list the specifications for your particular vehicle, possibly including the rear axle ratio. This is less likely to give you the exact differential model number, but it'll at least provide the gear ratio.
4. Check the build sheet (if available):
* From Dealership or Previous Owner: If you purchased the truck new, or if a previous owner kept the original documentation, the original build sheet will specify the options and components, including the rear differential.
5. Look at the sticker on the driver's side doorjamb:
* Options listed: This sticker usually lists many options and may include the rear axle ratio or other clues about the differential type. This is not a guaranteed method, but it's worth a quick check.
Important Considerations:
* Different Models: The 2005 Dodge Ram came in various configurations (1500, 2500, 3500, different cab styles, etc.). The differential will vary significantly based on the model and options.
* Multiple Possibilities: Several different differentials could have been used in a 2005 Dodge Ram, depending on the trim level and options selected. The gear ratio is the most common piece of identifying information you'll find.
By combining these methods, you should be able to determine the rear differential in your 2005 Dodge Ram. Remember safety first when working under your vehicle – use jack stands and follow proper safety procedures.
