There are two clear vent lines on the front of mine. One goes to the front/top of the front diff and goes up and tees into another line in front of the fuel tank. It is maybe 5/16 line, the other, smaller one (1/4 maybe) comes from the battery, down the right side (from front, looking at it) and goes down between the frame and front diff at the very front.

 

I believe it's a vent. I have one on mine as well.