Do a forum search on oil leaks on the V12 engine. This engine has lot's of "problems" with oil leaks. I think it's unlikely you have a bad rear seal. Sometimes a seal will shrink a little in storage, but they usually swell up again when they get "wet". Are all the bolts tight on the oil pan? Did an animal chew through a hose while in storage? ( Don't laugh, it's been known to happen. ) If you can't pinpoint the source of the leak on your own, I'd take this one to a professional.

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