What rear do you have? M226 (OR model or Manual Tranny) or the C200 model (X, S or SE w/ Auto tranny).

If it's the M226 then it's a Dana 44 variant rear end (though, no standard D44 parts will fit it).

But to answer your question, yes, standard threads and yes, fill to the bottom of the fill hole when level. If you have a lift, you might have to park on a slop facing down hill.

If it's the M226 rear it will take 4 1/4 pt of GL-5 gear oil (75w-140). You will also want to use Permatex Ultra Grey 82194 to seal the drain and fill plug threads.

If you have the C200 rear, you will need to get the gasket for the drain plug and use the Permatex Ultra Grey 82194 for the fill plug.

So, since I just ran at the mouth above...here are the specs.

M226 (OR model or S and X w/Manual Tranny) - Dana 44 Variant
Capacity: 4 1/4 pt
Gear Oil: GL-5 75W-140
Drail Plug Seal: Permatex Ultra Grey 82194
Fill Plug Seal: Permatex Ultra Grey 82194
Cover Seal: Permatex Ultra Grey 82194
Drain Plug Torque: 20 ft-lbs
Fill Plug Torque: 25 ft-lbs
Cover Bolt Torque: 31 ft-lbs

C200 (SE or X and S Auto Tranny)
Capacity: 3 3/8 pt
Gear Oil: GL-5 75W-90
Drain Plug Seal: Gasket (Nissan part) and Permatex Ultra Grey 82194
Fill Plug Seal: Permatex Ultra Grey 82194
Cover Seal: Permatex Ultra Grey 82194
Drain Plug Torque: 36ft-lbs
Fill Plug Torque: 36 ft-lbs
Cover Torque: 36 ft-lbs

If you take off the cover you will want to use Permatex Ultra Grey 82194 to seal it and the bolt torque specs are