Twin DF300APs - lower unit oil, discrepancy between the two colors

[RiggedRight]

When changing the lower unit oil on twin DF300APs, less than 100hrs on the lube...the port engine is almost black, and the starboard looks like new.

I know in the past, counter rotating engines from other manufacturers had different capacities and different gears, and would typically darken the oil quicker. Is this still expected of the newer selectable rotation lower units? Or should I be concerned of some other issue?

No water or metal present. It is just unnerving to see a big difference in color in such a short run time.

Thanks in advance.

[briscoe]

Do you think the hypoid oil was different brands? The oil doesn't contact combustion deposited from pistons, right? So it can't turn color from mechanical movements of gears, right? I'm asking. I have used a GL5 oil that wasn't Suzuki and it wasn't the greenish blue color. I think it was High Performance Merc oil that is more black/blue. As long as it was GL5 - 90wt, it's good. It had the same strong oil smell, right?
interesting...