SG or SF are petrol motor oil standards

SG and SF are uber old standards...prolly early 80's

what that means is that there are no additives or detergents found in modern day oils (the newest standards are SL and SM is the latest)

i can understand why they may have used 10w30 oil without additives which would be unnecessary(or harmful) to a gearbox

but yer...i agree with whats been said above

only use MTF