Good luck with your sale, buddy. I can vouch for the excellent condition of the differential and carrier as I pulled them from my car to do a full M3 rear end swap. The diff is NOT leaking fluid. There is a weep hole for internal ventilation (OEM) and when I had it stored some of the fluid exited through the weep hole and "stained" the diff case. Also, I RELIGIOUSLY changed the diff fluid with Redline every 30K miles.
EDIT: I also replaced the rear differential bushing in the carrier as preventative maintenance. It only has around 10K miles on it.
Last edited by wrecklessfool; 11-01-2012 at 11:34 PM.