Try not to run your motor with the drive up. Don't ever do it if possible.
If you do, the grinding marble sound is what you'll hear.
I don't think your gear lube alarm would or should go off if the level is down to the ADD line.
Should be lower than that.
I'd try running around the lake again, drive down, before any major maintenance.
I'll second that! Don't run the motor when the drive is all the way up (trailer mode). Rookie mistake on my part, and it resulted in needing replacement of the gimbal bearing. It was worn (1997 boat), and that finished 'er off! Sounded like a coffee grinder, but now it's smooth as silk.