The 1991 Jeep Wrangler (the YJ model) most commonly used the Dana 300 transfer case. Some early or special-build Wranglers also left the factory with a Dana 20, and over the years some owners have swapped in other units. Exact equipment can vary by production date, engine, and market, so checking the case itself is the surest way to know.
Factory configurations for the 1991 Wrangler YJ
The following transfer-case options were seen in 1991 Wranglers, with the Dana 300 being the prevalent original equipment in most U.S. market builds. A smaller subset carried the Dana 20, depending on the specific options and production run.
- Dana 300 transfer case
- Dana 20 transfer case
In practice, the Dana 300 was the default for many 1991 Wranglers, valued for its strength and aftermarket support. The Dana 20 appeared in a portion of early-year lines or in particular option configurations.
How to confirm the exact transfer case on your vehicle
To verify which transfer case your specific 1991 Wrangler has, use these identification steps. This list helps you avoid assumptions based on model year alone.
- Inspect the transfer case for a stamping or tag that identifies the model (for example, “D300” or “D20”).
- Check the physical appearance and mounting pattern of the case and its outputs; the two cases have distinct shapes and outlet arrangements.
- Consult the vehicle’s original build sheet, window sticker, or VIN-derived records to confirm the factory option list.
- If possible, compare the shift lever configuration and any included range selector to known factory layouts for Dana 300 vs. Dana 20.
Knowing the exact transfer case helps with parts compatibility, maintenance intervals, and potential future swaps. When in doubt, a Jeep specialist or dealership can verify the unit from the VIN and chassis data.
Summary
For most 1991 Wrangler YJ models, the Dana 300 transfer case is the standard setup, with the Dana 20 appearing in a minority of early or special-build examples. Because configurations can vary by production date and options, the definitive way to know is to read the transfer-case code on the unit or check accompanying build documentation.