Bit of a stupid question, but something i've wondered about from time-to-time so i thought i'd ask the collective....

First, i'd like to say i dont go near working on auto gearboxes, i dont know anything about them other than they work on myth and black-magic and should be left to the Wizards to fix - this is just my curiosity.

In an auto gearbox, does the torque converter get its fluid from the auto gearbox or is it a sealed unit with its own internal oil?