Have you ever thanked God for a week long sore neck? We are!! When we took the boat out last month I went down to get Warren some aspirin. That's when I felt the vibration. At first Warren thought the engine might be out of alignment, then maybe the shaft was bent. We took the boat out of the water today and removed the shaft and it looks fine. So we are taking it and the drive shaft coupling to a specialist to fine out if it is bent. There is some crevice corrosion in the shaft so that may necessitate replacing the shaft whether it's bent or not. We could have trashed our transmission if we hadn't caught this now. And that would really set us back! So thank God for needing the aspirin!!!!