Beneteau 40/KM35P trans problem

[JohnB40]

Hi Folks

2009 Beneteau 40
4JH4AE engine .... 1100 hours
Yanmar KM35P transmission (also called Kanzaki TTMC35P)

Works in reverse. When in forward it does not engage or only weakly. Then get revs up to about 1200 and it slams into gear. The cables are fine and the lever on the side of gear box moves easily and to the fullest extent.

Sounds like truly an internal problem. The oil (SAE 30 HD) is a bit black but doesn't smell burnt.
A friend suggests flushing numerous times with say SAE 10 to see if anything is stuck.
Any ideas?
thanks, John

 

[JohnB40]

Transmission cone wear

Hi
Just want to add to question.
Seems likely the cone clutch is "glazed" and slipping.
Repair experts have said cone can be "lapped" to make it good ... they do check wear not too great.
Any experience on this? Don't want something unreliable!!!

Thanks, John