It is # 14 on diagram. Those diagrams suck.

 

the white cannister is part number 04891685 AA (which was superceded by part 04891685 AB). the part that should be bought with this is the o-ring which is part 52129436-AA. the o-ring is what really makes that seal tight! the cannister sells for 9.80 at your local jeep dealership. the o-ring is 1.80.

all in all its about a 45 second fix. hope this helps

this is what fixed my 07 unlimited X

 

I as well am having the same problem. I think I need the o ring I do not remember seeing it.
So glad I found this thread.