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Discussion Starter · #1 ·
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 1800 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 or "plugged". I've no idea what's inside!!
Any ideas?
thanks, John
 

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If that is a cone clutch tranny, it sounds like the cone is worn. My 2GM20 had that problem (don't recall which transmission it had; your number sounds familiar, though yours is likely bigger but may still be a cone clutch). One shop lapped the cone, but that was a band-aid (for $800!) and not much cheaper than having it replaced properly. A worn cone slips until enough revs/power to get it to engage... until it's too worn for even that. I had to drive the boat thru Canadian Customs in reverse when forward would no longer work.


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Does your book ask for 30 wt or hydraulic trannie oil ? Either way it's not a biggie to put it on the bench for a look see. Then you can decide on fix or replace.
 

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Discussion Starter · #4 ·
The oil is engine oil ... SAE 30 HD (Heavy Duty).

Not very easy to take tranny out .... I guess depends on your experience and skilll level. It obviously needs to be disconnected from prop shaft hoping have enough room to push shaft back before prop hits rudder and taking care to secure the shaft. Unbolting from engine also not easy unless you are very slim/strong with very long arms. It is all pretty packed in and not exactly designed for most folks to take apart. Would help if a few bits of aft berth woodwork were screwed together rather than glued.
Really appreciate the info.

IMPORTANT FOLLOW UP:
Has anyone else had negative experience with "lapping the cone" which I think means getting rid of the glazed/slippery surface that is causing the slippage. As against replacing with a new piece.

John
 

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I had that negative experience - "lapping" initially "fixed" the problem, but only for about one season... Then it came back. Even worse, the marine lapped it a second time, which lasted even less. Combined wth their time charges (which included every time the mechanic had to walk from the shop across the yard to the boat), it was rediculous.

In the end, I removed the transmission myself with my wife's help, took it to a real Yanmar shop who replaced the cone, and reinstalled it myself, with the total number of hours coming to less than what the yard charged for their lapping band-aid. And it stayed fixed. So much of the work is getting to the tranny, disassembly and reassembly (including a couple of one-time-use seals) that replacing isn't that much more expensive.

Hope this helps.



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Redline: who and where did you take your tranny to get fixed? Also, what was the cost, if you dont mind sharing. Sounds like I'm going to be doing the same and just want to prepare the wife.

Thanks
 

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I took it to Diesel-Bec, just north of Montreal, Quebec:
1805, Lionel-Bertrand
Boisbriand (Quebec)
J7H 1N8

Telephone: 450 434-3401
Toll free: 1 866 441-3401
Fax - Adm. and sales: 450 434-1135
Fax - Parts: 450 434-2827
Email: [email protected]

It was several hundred dollars, I don't recall exactly as it was my previous boat, about 15 years ago. Maybe close to a boat buck, I was just glad to have it fixed once and for all.
 

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GREETINGS EARTHLINGS Have you checked there is plenty of scope for the gears leaver to engage in forward cable may be rusted or cinked AS ALWAYS GO SAFE
 

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Older thread but gear boxes are still wearing out as I type this.When in doubt, first remove the linkage and try it by hand at the shift lever.like flood said. Trannies are mostly cone friction type or discs and bands .like auto trans, disassemble, replace worn bits ,adjust, reinstall, check linkages and alignment
 
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