Woodz428,
I would have been quite happy if my trans was made out of aluminium and not this stuff I have, but the corrosion is very minor and no pitts or anything at this stage.
You are right it needs protecting, I have read where the grey/white surface corrosion can protect it a bit, but have since found on the web a product called "Gibbs Brand" this product has many uses including firearms etc and stop the corrosion for years, the magnesium may still go black but have a shiny surface, I suppose that is similar to metal anti rust preparations that form a potassium based oxidation surface!
I dont know what they have here in NZ, but I guess I can get a couple of cans of a suitable product shipped out, or a suitable spray gun
oil like G96 may do it, but they wont air freight aerosol cans.