The pcv valve on my truck is connected to a hose which connects to this tube, you can pull this tube out, If you follow this hose straight up from the valve cover it connects to an rubber elbow, this elbow is connected to a tube that slides out. What is this part called , and should there be oil in this part . Thanks for your help.

 

That tube is directing oil vapors from the crankcase into the intake.Yes it is normal to have some oil in it.