I recently had a used tranny installed and have noticed a leak in the rear tranny seal. I plan to bring it back to get it fixed. the leak is not big, more of a seep that doesn't drip onto the ground. will the atf degrade the new tranny mount? I read that it will kill the O2 sensor. there really isn't an overspray on the undercarriage aft of the rear tranny seal/shaft. the leak seems to just dribble down onto the tranny mount the metal bracket that hangs under the rear shaft. how long can I drive with a leak in the rear seal? is it catastrophic? thanks!