Background... 2004 5.0L Mercruiser (carb), Alpha 1. Changed gear lube when I winterized in October of 2004. Took boat out about 2 weeks ago for its spring shake down. Gear lube in reservoir dropped about 1/4 inch as expected. Took boat out last weekend to take the kids tubing. Ran the engine hard with lots of turning (not full throttle). Opened engine cover today and the gear lube reservoir was empty! Gear oil is in bilge. Checked reservoir and hose leading to outdrive. No apparent leaks. Not sure where it's coming from. Any ideas?