[Skyline2.0]

Can anyone that's done a rear differential drain and fill, either DIY or at the BMW Service Dept, confirm whether the correct fluid is Hypoid Axle Oil G1, G2, G3 or G4?

I see multiple options, and it looks like newtis is pointing towards G1...however I'm unsure as the dealer I spoke to says the X1 xDrive uses G3. Can anyone confirm the proper gear oil?

Also, is this service a straight drain and fill (with no special diagnostic tools needed)? I ask because it looks like certain types of differential work requires a dealer-level scan tool to bleed and calibrate the differential clutch. I'm just not sure whether a routine drain and fill would require this type of extra work.

Thanks.