Symptoms
Gear oil on the skid plate, wet yokes or a drip from the rear output. The Dana 300 holds only 2 quarts, so a slow leak can starve it.
The fix, step by step
- Drain the case and unbolt the driveshafts.
- Hold the yoke and remove the output nut, then pull the yoke.
- Pry the old seal out with a big screwdriver or small pry bar, and drive the new one in squarely with a seal driver or a large socket (one owner used a 1 1/2-inch socket), tapping gently so it doesn't distort.
- Inspect the yoke's seal surface and replace it if it's grooved.
- Many owners take the chance to switch from strap-style to U-bolt yokes.
- Refill with 80W-90 to the fill plug.
Tools & part numbers
- Yoke holder or pipe wrench
- large socket for the output nut
- pry bar
- seal driver or 1 1/2 in socket
- 80W-90 gear oil.
Where to buy the parts
Crown 300GK Dana 300 transfer case seal kit, 80–86 CJQuadratec (Crown Automotive) ↗Amazon ↗
Crown Dana 300 rear output shaft inner bearing, CJQuadratec (Crown Automotive) ↗Amazon ↗
Yukon 80W90 conventional gear oilQuadratec (Yukon) ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Jeep CJ-7 parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.