[az_240]

So the car makes no noise with the open diff? (Transmissions can make a whirring sound on decel too...input shaft bearing)

If you're sure it's the 2 way making the noise I'd crack open that pumpkin and put some white grease on the teeth to check contact patch and check for side to side play while you're at it. Wipe clean when finished.

If everything is solid try spinning the diff to see if you can hear anything from any of the 3 bearings. If the pinion bearing is bad just swap pumpkins. If the output/axle bearings are bad you'll probably have to order new ones from Tomei or OEM Nissan which may have to be pressed on.

Yes you'll want to use all the same hardware inside the open diff. Install it the exact way it came out. Bearing caps, shims, bolts and everything. I'm not sure it's necessary but I even swapped the ring gears and made sure all the bolt holes were centered. It's really not that hard to do if you have the proper tools.