What Yamato gear oil brand and viscosity are you using?

[ZUL8TR]

80 Manual states fill with good quality gear oil, 102 & 302 manuals has fill with GO-90.
On the 80 just changed prop and drive shaft ball bearings and seals on these shafts and want to see what is being used.
Thanks

[nail33]

I use Amsoil synthetic marine gear lube 75w-90 in both my Y80 and Y321:
https://www.amsoil.com/p/amsoil-synt...be-75w-90-agm/

[DeanFHobart]

I use Amsoil synthetic marine gear lube 75w-90 in both my Y80 and Y321:
https://www.amsoil.com/p/amsoil-synt...be-75w-90-agm/

That is a very good choice.