Thanks for your prompt reply 4square! I found some Lucas marine gear synthetic oil 75wt90, does this sound like it will work good? Also, I see a 3rd set screw oil hole right on the top of the out drive for the upper drivetrain lubrication, like you said for the upper half. How high should I fill this reservoir? I spent hours reading this entire forum and I am amazed at the amount of knowledge of these AMPS boats everyone has here, This is like the AMPS hobbies go to handbook!