Transfer case and driveshaft question

[joners]

I have a 2003 Explorer XLT

I noticed the other day I could see a vaccuum line by the oil filter that appeared to have a plug in it. Today I went under the truck to see if I could find where it went to, it went to the transfer case. The plug in it is a pan head body panel clip. I couldnt really see if it's supposed to be hooked up to vaccuum or if it's just a breather. Can anyone confirm? The plug in it has a slot down both sides so it can breath. I had the transfer case done awhile ago and perhaps the shop put it in if it's a breather so **** doesnt get in there?!?

Also the front axel driveshaft has movement at the transfer case end, I thought my wheel bearing(s) were going because you can hear some clicking noises while driving. It has movement every which way, and the boot is torn. I am assuming this is to be like any other U-Joint and have no movement as well?

 

[cemedlin1]

i think i have a problem with transfer case

just had tranny rebuilt but nothing to transfer case. now service eng light came on and sad vacuum leak and something with transfer case. the tech assumed the vacuum leak was from the engine. the transfer cae codes being seperate. but now that i have seen your post i think they are connected.