I believe that is the Dana 35
Yes it will same models and everything.
Dana 35 or Dana 44
80w90
I'd look at the pinion bearing first. It's near the end of the rear end.
80w90, if posi it requires friction additive.
Generally it is the Dana 35, and 44 models
You can go with 87 thru 1995 for a direct fit.
Yes, the 35 is the standard rear end, 30 up front.
The 35 is standard, but the 44 is an option in that year and is found on the Sahara.
what front and rear end are in a 2001 wrangler sport 4.0
It's a little vague, but check your u-joints, that would cause a sound when driving.
no, they are entirely different vehicles