This is a 1997 alpha 1 Gen II drive, merc 5.7-2barell. I've removed the lower and upper unit of the drive to fix a minor oil leak...I caught it right away and didn't find any water in the drive. I still learning and relatively new to boats, but being a nervous Betty, I'm always questioning everything that just doesn't seem right. The drive runs fine, other than the leak that I just fixed, was the gear shift bushing, and there haven't been any perfomance issues. the drive shaft and u-joints in the upper unit spin very smoothly and freely. But the drive shaft in the lower unit just doesn't seem to spin nearly as smoothly as the upper one. I've removed the water impeller assembly to make sure that wasn't making it bind and it spins much more freely with the impeller removed. There seems to be about a 1/16 inch of verticle play in the lower drive shaft. Basically when I pull up on the lower drive shaft, I can see it come out ever so slightly, maybe a 1/16 inch. It doesn't matter if it's in gear or not, I can hear what sounds like a slight rattle or metal rubbing sound when you spin the drive shaft. The prop shaft spins freely and smoothly when it's out of gear. Also, when I pull upwards on the driveshaft and I spin it, it seems like this rattle sound goes away and it seems to spin much smoother. Does this sound like it's normal or does it sound like this may be the start of a larger problem. A freind of mine who works on boats said that it sounds normal to him and that the lower units usually don't spin as smoothly as the upper units, but it just doesn't seem right to me. I would really hate to tear into the unit if this is just the way Alpha's run. Thanks for anybody's opinion.
