Front axle leak

I found a leak on my front axle where the drive-shaft bolts on. It looks like the seal behind the yoke. Is this difficult? If so how much will the shop charge to do it. And is it worth doing.


'98 Tahoe LT

I didn't have time to check, and was wondering if there is a nut that holds the yoke on? Then I guess taking that off I'd be able to replace the seal
Any help?
Jim