Dana 30 service?

My pinion seal is leaking. I presume it is worn bearings due to misallignment and drive line vibes. Is this a difficult fix? Can the bearing be removed from the outside or does the pumkin have to be gutted?

I'd try just replacing the seal. The bearing can be removed from the outside; however, you'll need a new crush sleeve to get the preload right when you put in a new bearing. To measure the preload correctly, you really need to remove the carrier. If you do replace just the seal, you'll need to marked the pinion end, yoke, and pinion nut so that you can put it back together as it was when removed. This will keep the preload at least the same as it was before you started.