Red Line gear lube question(s)

[Matthew Killick <m.killick@domain.elided>]

This weekend's schedule includes replacing my Giulia 1750 TI gearbox with a
newly re-built unit.  Over the years I've seen plenty of raves about Red
Line gear oils, (which is available in Australia, AU$22/litre) but it
doesn't seem to match Alfas specs.  My under-bonnet sticker calls for a GL1
oil, but both the MTL and MT90 oils are GL4.  I am under the impression
that the degree of friction maintained is an issue as far as the working of
the synchromesh is concerned, and that there may be problems of corrosion
of some metals in the box, depending on what additives are present in the
oil used.

So, does anyone have a justification for the use of a GL4 oil in general
and Red Line in particular?  I assume that if it is appropriate, then the
MTL would be the correct choice.

Cheers
Mat

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