I just wish I could find what is the trigger to make this happen. It is so random at this point.
Someone suggested that it might be the u-joints. It does sound/feel like it, but when I replaced the gimbal bearing last week they looked great and were not sloppy. I even greased them.
The prop is on good (brand new) and this happened with the other prop as well. There is no play that I can feel or hear in prop shaft.
Could it be something to do with the drive coupler? It isn't slipping. I will pull the drive again I guess. What do I look for?
When I was putting the drive back in, the last 2 inches needed a bit of a kick to get it in all the way. Could this be the issue?
I could not perform an alignment test as I did not have access to the tool here. (remote area). I was making one on my lathe to specs but the damn lathe stopped right when I was near the end! Nothing is going right!

its a Alpha one gen 2 not phase 2.

Intermediate shift cable needs adjustment and or replaced. Prob bellows and shift cable bellows getting old anyways time change or really checked out. Your boat was year model 90 s so has any of that been done ? Hours mean nothing here. Father time does.

No idea if it has been replaced. Boat was just given to me a few months ago. But that is a good point. I will verify how the operation of all that is. Do you think the cable is out of adjustment? What do the bellows have anything to do with it? Aren't they just rubber casings? They, however are in excellent shape and condition. Someone must have tended to those in recent years. Totally dry inside.