Trans Noise (Clanking) at Idle while in Neutral

[dsendre]

Just splashed this past weekend and noticed a new noise coming from the port trans.  The video linked below is an example of what I'm hearing when the throttle is at idle and the trans is in neutral.  If the throttle is increased at all or if the transmission is put into gear, the sound goes away.  Is this an issue with the damper plate or a larger issue?  Any help/suggestions would be appreciated but I'm pretty sure I'm not moving the boat again until I have this figured out.

2002 3100 Open.  8.1L Crusaders, ZF Hurth Trans.

https://youtu.be/pJ71wbSoELo

[jclark003]

Hard to tell from the sound but it's not unusual to get noise from gear lash that can be amplified by a miss in the engine or weak/broken springs in the damper plate. Usually the sound is most apparent at idle and in gear but it can certainly happen out of gear. Before worrying about the damper plate make sure your engine is on a razor sharp tune and has no misfire. you can also try changing your idle speed to see if that clears it up. Some owners will also change out the transmission oil with a light weight engine oil (20w).

[dsendre]

Thanks for the response.  After talking with some other folks I went back to the boat tonight to double check all my spark plug wires were tight and hooked up correctly.  Compared every wire on the port (problem engine) with the starboard (working fine) and realized I crossed a set of plug wires.  Swapped them back and she’s running great with no clanking!

https://youtu.be/hCPOlvhGSNY

[jclark003]

Yes that will indeed cause the gears to chatter. Glad you got it solved.