What brand 90 wt gear oil do you all recommend using in the planetary gears on an excavator??? Where the "sun gear" is?? I want to use a good-name, long-dependable oil
CAT TDTO 50 would be my choice. It's a 50 weight drivetrain oil, which is oddly enough equivalent to a 90weight gear oil, only without the smell. We've had excellent service with it.