I have never done this so I surprised at the sound of the shaft turning while on the trailer. So here what happened, I was changing my fluids this morning and once I was complete I told my boy to hook up the water and start up the engine and let idle for awhile. Well he accidently put it in gear and the most horrific sound came from the shaft as it turned. He immediately turned it off so the question is do you think there is any chance of damage? Since I have never put in gear while on the trailer I am not sure what the "normal" noise would be, I imagine this would be normal with no lubrication on the shaft.

You are more than likely to be fine. Was it a squealing sound? Turn it by hand and see if its the same thing.

That's normal. Water lubricates the strut when it's in the water. I doubt you did any damage.

Ok, I just turned the shaft and the sound is at the shaft support near the prop. I sprayed some water around the shaft support and it appears the noise was due to it just being out of water with no lubrication between the shaft and shaft support.