Let me google that for you
Follow these simple steps
1. Mark the driveshaft to the yoke before removing the driveshaft. Careful not to release the needle bearings in the u-joint.
2. Mark the pinion, nut and yoke with a straight line for re-installation later.
3. Remove the pinion nut.
4. Pull seal out, lube the new seal before installing it
5. Reinstall the pinion nut and tighten to the same location as before, then turn 1/8 of a turn more, this will preload the bearings in the pinion shaft. [Use red locktite if re-using same nut]
6. Reinstall yoke and driveshaft to same position as before. [Use some sealant on the inside of the yoke to keep oil from seaping through the splines.