So I was looking underneath and found this heinous black "wire" - appears to be hollow with nothing inside? Located near my front left tire, under my seat kinda.

Any ideas? Safe to remove?

 

That's your differential breather tube. Follow it up and there's a little plastic bulb on the end. The frayed end connects to your front differential , on the dana 30 it's on the upper left hand side (sitting facing the front of the jeep like you were sitting in your seat) of the diff.

Buy a replacement tube and splice em together or replace the tube completely. I wouldnt remove it, axles gotta breathe and having the hose up towards the top helps water and gunk not get in it. make sure to route it away from the axle and it won't fray again.

edit: some people call them vent tubes, they're for letting the air expand in the diff while not building up pressure.
Josh

 

Nailed it

Definitely want to keep it vented up where water and debris won't get it in it. If it gets plugged up, as your front diff gets hot pressure builds up and it will cause your axle seals to leak.

 

And change your diff fluid for good measure.

 

Thanks all

 

My vent tube is zip tied to the upper control arm. Keeps it out of the way. Leave slack for suspension travel.

 

***-frayed wire is pretty ugly.