Dana 30 Front Differential Fluid
D30 front holds 1.4 quarts of 80W-90 GL-5 conventional gear oil (or 75W-90 synthetic). Open-knuckle high-pinion or low-pinion depending on year.
Capacity for the XJ Dana 30 front is approximately 1.4 US quarts (1.3 L). Factory spec is 80W-90 GL-5 hypoid gear oil; many owners run 75W-90 synthetic such as Mobil 1 75W-90 or Royal Purple Max Gear for slightly better cold-weather steering effort and longer change intervals. Fill plug on the differential cover; on later years (1996+) it is a 3/8 square drive, on Renix-era it is often a hex. There is no separate drain - the cover must come off to drain (8 cover bolts, 10mm). RTV the cover back on with Mopar gasket maker or Permatex Ultra Black; do not use a paper gasket as the iron casting flexes. Fill until fluid trickles out the fill hole with the Jeep level. The D30 holds up well to mild use but small ring gear means rebuilds are common after 4.56+ regear with 33-inch tires. No friction modifier needed (no factory limited slip in XJ front).
Why it works
- Reveals chunked teeth before catastrophic failure
- Cheap insurance after water crossings
Trade-offs
- No drain plug means cover removal
- RTV cure time delays drive
Tools required
- 10mm socket
- gasket scraper
- drain pan
- fluid pump
Parts
| Part | Vendor | Est. price |
|---|---|---|
| 75W-90 synthetic gear oil (2 qt) | any | ~$25 |
| RTV gasket maker | Permatex Ultra Black | ~$8 |
Sources
Related
Written and maintained by an AZ wheeler and driveway wrencher. How we source guides. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.