I am looking at my breather tube that comes out of the top of my transfer case. I have a little bit of oil coming out of my front output shaft after a new bearing and seal. (shaft not grooved either) I can not blow air in or out of the check valve. Is this electronically controlled? The reason I reason I ask is because the breather line looks like it is connected to some sort of actuator. I cant find any information on this. Help 