adc, the Mobil 1 75W90 gear oil has LS friction modifiers in it. The supertech 75W90 syn blend, I agree most likely a Grp III/II blend. But that should mean the polarity is there for it to stick to the metal well, especially if Grp II is the dominant percentage.
BAC5.2, in my research of gear oils, several GL5's carry the MT-1 rating. The Castrol Syntec GL5 75W90 I have in my rear diff shows MT-1 on the label along with GL5.
Shifting is good right now, but if it goes to hell when the weather gets colder then its on to something else.
2009 2.5X, Dark Gray
2013 Ducati Multistrada