Gear Oil Equivalents

[Paweave]

I am working on getting a 1964 MZ ES150/1 back on the road after sitting for several years.
The shop manual calls for a GL60 gear oil which is impossible to find in the USA. The specifications for the GL60 is;
Viscosity at 50c - 53 to 68 cSt
Power point max - 25c
Flash point - 180c
H2O content - 0.1%
Any recommendations on a modern oil that would be equivalent?
Thank you in advance for your assistance.
DW

[Blurredman]

sae 80w transmission oil (no greater than gl3 spec), I should imagine.

[Paweave]

Thank you Blurredman. Much appreciated.