Kanzaki transmission question

[rbyham]

am trying to track down a new noise emanating from my engine compartment. The engine is a 1978 Yanmar 3qm30 with a bolted on Kanzaki transmission. The ID plate says KH18.

The sound is like that of those Mexican percussion instruments that are shaken. I think they are called maracas and have the sound of dry rice inside.

The sound only happens in gear and more so in forward. I also notice that when put in gear I hear a solid "clunk" sound of engagement. A local mech told me this is a good sign on the trans as a smooth gradual engagement indicates plates going. Not sure on that one. Anyway I was wondering if folks here who have experience with this setup might have some ideas for me as far as indicators on the trans or other potential sources of the noise. Thanks...

Also the tag calls for atf-a.... What brand are folks using?

[four winds]

I wouldn't worry about the clunk. But might be good to check the shaft key and keyway. A problem there can cause a more pronounced clunk. All the slack in the tranny and shaft add up to make that clunk.

New noise...... has it gotten worse since first hearing it?

The sound you describe sounds suspiciously like a worn bearing. If it gets louder you may be hearing an eminent failure coming.

Consider that a severely faulty cutlass bearing could transmit sound up the shaft to the tranny coupling.

How's your engine alignment? It may have shifted, stressing a bad cutlass or causing the shaft to rub against the stern tube.

[shakey doug]

Use a listening rod around the bellhousing area and check out the drive plate [ damper plate].

[S/V Antares]

Disconnect the shaft and see if it is still there ....

[rbyham]

Thanks folks... condition of cutlass is unknown but suspect it is toast. Boat is new to me in February. Have been doing in water refit since. Was hoping to get to cooler months (December) to haul and do bottom/cutlass. One more possible clue is when sailing with trans in neutral I hear prop turning but I can literally tell rpm from what sounds like high side of prop. Would be much happier to find this a cutlass problem than a trans problem. Not sure what to do next. Fluid needs changed so will do that and see if it makes a diff.