Re: 99 crownline 7.4 gear oil replacement
John,
Several things come to mind which could generate an audible alarm at the helm. One would be the depth gauge. The others would be from the Merc monitoring circuit which monitors high engine cooling temp, low engine oil pressure and low outdrive lube reservoir level.
If you filled the outdrive lube reservoir to the "full" level, add a touch more lube to see if the alarm/noise stops. Another way to check to see if the lube reservoir is generating the alarm is to disconnect one of the wires which come from the reservoir. The connections are a simple bullet type connection that pulls apart.