DO NOT USE THAT SYN5 OIL IN YOUR MECHANICAL DIFF
from experience it is no good, you need a mineral oil, with the ls additive in it.
i have spent many many many hours trawling through the internet to find out the oil it should have, and the fully synthetic is very bad for it.
also gt gearboxes are gl-5 compliant, whereas the glanza boxes are gl-4 compliant
Like I said, you now have a conflict of interest. A mineral oil with LSD additive is not going to be doing your gearbox any favours if your running high power through it and use it hard.
So, do you go with what the gearbox wants or what the diff wants as they are two different things.
Can you link to the info that says KAAZ fwd lsd's (fed by the gearbox) require mineral oil only?
Cheers
Guy