* The sticker on the driver's side doorjamb: This sticker usually contains a lot of information about the vehicle, including the axle ratio. The axle ratio is *part* of the axle code, but not the entire code. For example, you might see "3.55" indicating a 3.55:1 ratio. You'll likely need to cross-reference this ratio with a parts catalog or online database to get the full axle code.
* The axle itself: The axle housing usually has a casting number stamped into it. This number, often including letters and numbers, provides more detailed identification and is more likely to be considered the complete axle code. However, locating this requires getting under the truck and might need some cleaning to see the stamp clearly.
In short: You can't determine the rear axle code without looking at the vehicle itself. Use the door sticker as a starting point, and if you need more detail, check the axle housing directly.
