What is this?

[nghiS4]

I just finished greasing my zerk fittings, and came across this loose hose, above the black box left of the center differential. It's slightly cracked at the end, and it seems like it should be attached to that nipple. What is it, and do I need to repair or replace it? The truck has run perfectly and still does.

 

[LobstaMobsta]

Not sure either vent or vacuum. This is on transfer case? Where does the other end lead?

 

[BlackWorksInc]

Its a vent, just put a new length of hose on the nipple if its cracked.

 

[nghiS4]

Would that be the center differential/transfer case breather/vent into the engine compartment? Guess I still should do the rear differential breather mod...