An oil thread but , In searching for info related to a synthetic gear lube that would be ok for both Gl4 and Gl5 applications I came across this very straight forward comparison of some of the commonly available brands. I have been using the Valvoline for both the gear box and the carcs in both a griso and a 1400 custom for years now with no drama. I guess it's not a bad choice so I am sticking with it. Thought I would share the link.
https://bestsyntheticoilguide.com/synthetic/best-gear-lubricant/
