Re: alpha one outdrive fluid.
With the drive down, on the port side of the upper unit is a screw, that is the vent, and also the level at which the gear lube should be. When you remove the screw, lube should be at the level of the bottom of the vent hole. It is drained and filled from the screw on the bottom port side of the lower unit. You fill it with a pump from the bottom to make sure there is no air that gets trapped. I'd use Quicksilver High performance gear lube. When you fill it, you fill until the lube starts to run out the vent hole.
