The rear end is a Dana 44 3.73 and It had a tag on it saying it needed limited slip additive. I have not gotten into the carrier to see if it has the clutch packs or not yet. If I Rember right when it's on stands the tires rotate opposite directions
If it had a tag saying it needed friction modifier, I'd venture to say it has a limited slip. I doubt any PO would just put that tag on there. If the tires spin opposite directions, the clutch packs are worn out. Whether or not that's causing your noise is a different story.
01 TJ - 4.0L, NV3550, 2" Skyjacker budget boost, Xenon flat flares, Trail Gear front bumper, Tuff Stuff rear bumper, RH4X4 sliders, 33" STT Pros on 15x8s