I'm looking at buying a 2002 Z28 convertible with 12,000 miles. Most everything looks great, but it has a weeping pinion seal. It doesn't drip, but you can see where there is some evidence of weepage. Is this common? How big a problem is it? How difficult is it to fix? I'll try to attach a link to a picture below.

http://pg.photos.yahoo.com/ph/mcdhemman/album?.dir=d828

 

Very common problem.