Lower Unit Issue

[FFMike462]

I have a 1998 Mercury Mariner 115hp and I drained the lower unit gear oil and it came out Milky and had a collection of shavings attached to the screw. I unfortunately cannot upload the picture here, but I do not believe the oil was changed in 4 years. I changed the water pump/impeller last year, so not sure if that would have any bearing on this issue. Any suggestions what it could be? What further diagnostics I can do? I am new to boating and rely heavily on internet resources, so any information would be greatly appreciated as I would like to avoid the mechanic if at all possible. Thank you.

 

[racerone]

Take the propshaft bearing carrier off and have a look at the gears.-----Not hard to do.