You might also want to check the O ring in the differential adjuster. I thought I had a seal leak, changed the seal and it  still leaked. I took it to a pro and they changed the O-ring and it's been fine since. Took special tools and careful removal/replacement on the shop's part.

The leak was big enough to leave oil on the back hatch and also an 4" spot when parked.

On Mar 30, 2011, at 7:36 AM, Mike S <mikes@FLATSURFACE.COM> wrote:

> At 10:25 AM 3/29/2011, Joe T. wrote...
>> Seal is vigorously leaking after 48 hours of driving.  Looks like I'll
>> be
>> re-doing it again.  Back to Ultra Black.
> 
> Can you tell where the leak is? Is there a groove worn in the flange,
> where the seal rides? That often happens over time, then seal can't
> make good contact there, and just get torn up. I've had limited success
> using a Dremel with rubber polishing points to smooth out the groove to
> make things better. You have to be careful to keep it concentric, I
> spin whatever slowly while polishing to try and avoid any wobble.
> Otherwise, new or get it welded and turned to spec on a lathe.
> 
> If it's leaking from where the seal mates with the tranny - then the
> seating surface is probably scratched/damaged, or the seal got damaged
> going in. It shouldn't leak there even without any sealant (Hylomar or
> Ultra Black) used. Sealant only takes care of "weeping" leaks.
> 
> Ken mentioned the vent - good call, the seals definitely won't hold up
> to pressure.