Hose hangin, Where does it go?

So today i notice a hose hanging under my truck ( 95 jimmy 4.3 4x4 ) near the passenger side towards the back of the engine, crawled underneath and it appears to be coming from the top of the tranny/ transfer case(vacuum line maybe). Any help with what it is and where it connects to? Thanks in advance. I can try and get a pic up if that would help.

A picture might help.
There should be a vent tube/hose from top of transmission for venting transmission pressure.
Make sure it is not pulling vacuum.
Try to trace the hose to the other end and see if it goes to top of transmission a 1/3 of the way back.
If so it is a vent hose.
Just take a cable tie and tie it someplace on the side of transmission.
Is 4W and everything working ok?
MT