Re: '96 Explorer Front Diff
It may have a vacuum-activated axle. Does 4wd still work with it hanging?
Other than that, I could only imagine that it exists as a breather, but there is hose instead of just a hole in the differential so that it can have more water fording capability without so much risk of water entering the differential. I have some brilliant 4x4 connections- I'll make a couple of phone calls tomorrow and let you know what I find out.