[blazee]

He may be talking about the vacuum switch on the transfer case. When the tranmission seal goes bad and over fills the transfer case, it often damages the vacuum switch. Then the faulty switch normally fills the vacuum lines up with tranny fluid, which pretty much disables the 4x4 and the sometimes even the a/c controls. The switch is usually the culprit when people complain that their vacuum ball is full of tranny fluid.