How to identify your rear axle:
1. Check your owner's manual: This is the best source. It will specify the type of rear axle and the recommended fluid.
2. Look at the axle tag: The differential usually has a tag or sticker on it, often located on the differential cover itself. This tag may list the axle ratio (e.g., 3.55, 3.92, 4.10) and sometimes the axle type (e.g., Chrysler 8.25, Dana 35, Dana 44).
3. Visual inspection (less reliable): While not as accurate, you can visually inspect the axle. The size and overall appearance can offer a clue, but this is not a definitive method.
Once you know your axle type, you can determine the correct oil:
* Oil Type: For most 1997 Dodge Ram 1500 rear axles, you'll likely need a 75W-140 gear oil. Some may specify 75W-90. Check your owner's manual or the axle tag for specific viscosity recommendations. Do not use ATF (automatic transmission fluid).
* Additives: Some rear axle oils contain limited-slip additives (if your truck has a limited-slip differential). Check your owner's manual or axle tag to see if this is necessary. Using the wrong type of additive can damage your differential.
* Quantity: The capacity varies based on the axle type. The owner's manual or an online parts database (using your axle's identification number) will tell you how much oil is needed.
In short: Don't guess. Find your axle type using the methods above before buying any oil. Using the incorrect oil can severely damage your rear axle.
