Alright, transmission oil changed! And what a super easy job it is, I completely forgot that the viscosity of transmission oil is WAY thinner than the differential oil - OS Giken oil is 80w250 and it's horribly thick, it takes ages to pump it via hand pump, while transmission oil being only 75w85, goes super fast. Changing it was a breeze.
Tomorrow registration, can't wait to go for a ride!