Hi again, my bowtruster says Gear
Found another thread on internet
Quot: You should be able to use a SAE 90 oil which is a GL5. I use a Royal Purple synthetic oil in a 80W90 and it is also a GL5. I was just at Advanced Auto Parts
and they had the SAE 90 and so did Walmart. I use the 80W90 in all the gear
boxes and change it once a season in the snowblower and the mower gear box. End Quot.
This clarifyes a little bit on the way
The viscosity is a way to make the oil seal
different gaps, thats why you should never use full syntetic oil in an old engine, it will just leak.
Summarizing so far:
I think I will be able to use AGL-5 in at least my engine gearbox
and my bow thruster, or at least AGL-4 depending if there are any yellow metalls involved.
When the manufacturer recomends a specific type of oil the also concider the metallurgic of the parts
lubricated, that is actually my biggest concern.
Back to my question, is there anyone out there that uses engine oil in all the gearboxes in its boat