Engine knock

[tgrafx1]

I developed a knock in motor this weekend. Would only notice while in motion on the water. Seems to run fine when out of gear. Brought it home to inspect closer. Disconnected drive shaft to be able to run in gear. Started up an ran through low to high rpm out of gear. Put in gear and knock started. I am thinking transmission now. Anyone ever had this problem. Suspect: impeller went out a couple of trips ago and got hot a few times. Realizing the trans cooler is inline on the impeller line.

[michael hunter]

Flywheel damper plate?

[tgrafx1]

That was another comment I got locally today. I will pull it and find out.
Thanks

[DAFF]

Broken spring in the dampener plate would be my first thought too. When it was in the water would the noise change pitch in forward to reverse or with acceleration ??

[tgrafx1]

Damper plate and flywheel OK. Transmission ordered. Thanks for the comments.