front differential leaking
 

I have a 1984 S-10 Blazer 2.8l, i noticed my front diff was leaking from this cable. The shielding on the cable is cracked in a couple of places and that is where it is leaking the gear oil. I am pretty sure the cable is used to engage the front wheels when put into 4 wheel drive. Can anyone tell me what the part is called so I can pick up a new one. Also when replacing the gear oil should i use 80w 90?

Well today I figured out it is just called a shift cable for the front drive axle, pretty obvious. I am going to look into getting a new one tomorrow.