Quote:
Originally Posted by Ladogaboy
As far as I understand it, GL-5 can be used for both GL-4 and GL-5 applications, but not the other way around. Is that correct?
|
Not always. The GL-4 rating is also safe for yellow metals, GL-5 doesn't have to be. If you have something old with Bronze gears or bushings you need something with a GL-4 rating. Oil can have both ratings at the same time.