I am back into boating and bought a 2000 Maxum 2300sc with 7.4 MPI and Bravo 3 sterndrive. I have never had or been around a Bravo three. When spinning the the props by hand, I can hear a whirring noise similar to a bearing that is too tight. No play in bearings and it is smooth. Cannot see any metal in the lube oil, but I will have it analized to be sure. I can hear it in the water too, muted a bit because it is under water. I do have a slight vibration under way, but one prop is slightly dinged which I think is causing that ( props will be repaired soon). Is this whirring noise just normal for the Bravo three outdrive???? What synthetic gear oil do you recommend for the outdrive, I suspect the factory oil is not synthetic and I want to change it. Previous owner had it 6 years with no issues.