Motul Gearbox fully meets 915 specs like sayd by our member Peter.
It's an 80w90 dino oil reinforced with molibdenum.
While I agree with swepco to be a good oil for our trans i have to say that Motul is equal or better in my case. .... as said tons of times.... it's a matter of taste.
Also, in my country, italy, it's easier to find and this mean that i can change it often!
Here is a reference:
https://www.motul.com/it/en/products/gearbox-80w90