Transmission Problems

sord · **Posted:** 12 Feb 2008 20:14

My Tartan 37 is 1981 vintage and I am having a problem with the transmission. There is no discernable change in the feel of the control between reverse, neutral and forward which makes it very difficult in tight quarters to tell where I am going. The local marina (only one in town) wants to rebuild the transmission for almost $2000 but they have shown no regard for my money in the past and I think again in this is this case.
Questions are
Has anyone had this problem or know what it is?
Does anyone know the solution?
How difficult is it to rebuild the transmission (I have truck mechanic friend who would help)?
Thanks

Tortuga's Lie · **Joined:** 27 Oct 2006 10:32 **Posts:** 827

Which engine/transmission do you have? Mine's a Westerbeke 40 with a Hurth transmission and I've noticed a "clunk" when i shift into reverse. of course the thing is 30 years old now..... Shocked

Ardea · **Joined:** 19 Mar 2007 16:40 **Posts:** 195

Here's a replecement transmission for about $1K. Does your marina fly the Jolly Roger over their office.

http://www.marinepartsexpress.com/trans ... agodDz8T4A

Jim

Down2TheC · **Posted:** 18 Feb 2008 13:40

Tortuga's Lie wrote:

Which engine/transmission do you have? Mine's a Westerbeke 40 with a Hurth transmission and I've noticed a "clunk" when i shift into reverse. of course the thing is 30 years old now..... Shocked

Careful there! Our "clunk" from neutral to Fwd or Rev became more pronounced each season. I kept thinking it was my imagination until finally the shaft key was eaten up and the shaft pulled out of the coupling.

Assuming it's the same as the W50 setup, I'd highly recommend that this spring you back out the two set screws, undo the four coupling bolts and se if you can pull back the shaft half of the coupling to inspect your shaft. Had I done this I would have seen the set screws had eaten away at the little dimples, and the key was worn away such that it had a Z shaped cross-section. You may be able to at least visually inspect the key without disassembly. The more the key lets go, the more all rotational and thrust forces are solely on those set screws.

After drilling in deeper and replacing the screws with something that actually inserted into the shaft a bit, the clunk was gone. We later replaced the shaft. After wrapping a line around the screw last season, I'll be checking it out this spring. That's a hard way to stop a diesel at 2000 RPM.

Sorry for the digression, back to the trans.

Down2TheC · **Posted:** 18 Feb 2008 13:51

sord wrote:

There is no discernable change in the feel of the control between reverse, neutral and forward which makes it very difficult in tight quarters to tell where I am going.

Not sure what you mean here. Are you saying you don't feel any thrust? Does the boat get up to speed on power? Does it still have stopping power when you're coasting into the slip and toss it in reverse and juice it?

Our stock screw really lets us know when you gun it in reverse. Cavitates big time and rumbles the cockpit. But on a windy day I've often thought I was in N because the ambient commotion obscures the normal feel. I certainly wouldn't dump $2k until you know that the trans isn't doing it's job. No idea how you'd test for slippage though. (you could always throw a line at the screw and see if it stops the engine. Razz

)

Also, see the above post. Rule that out as well. You could potentially get slight slippage on a shaft if the key was shaved flat or gon and the set screws have carved a groove in the shaft. I'll take a pic of our old shaft to illustrate. It's improbable, but possible I'd think.

Tortuga's Lie · **Joined:** 27 Oct 2006 10:32 **Posts:** 827

"Careful there! Our "clunk" from neutral to Fwd or Rev became more pronounced each season. I kept thinking it was my imagination until finally the shaft key was eaten up and the shaft pulled out of the coupling."

That's good to know, I'll be hauling this spring anyway, so I'll be checking that out!!!
Thanks Cheers

Down2TheC · **Posted:** 19 Feb 2008 07:11

Forum tip...

When you're posting, if you select any part of the posts below, you can hit a "quote" button and it will quote just that. And you can do it as many times as you like.

sord · **Posted:** 05 Mar 2008 21:42

My problem is not that the boat does not respond it is just I cannot 'feel' reverse, neutral or forward. It just seems to be one continuous range with no clunk or 'vacant felling' that is neutral. I never know if I am in reverse or neutral or forward when I am in the mid zone. Of course it is obvious if the lever is full forward or reverse. I seem to have full power at the extremes

Down2TheC · **Posted:** 05 Mar 2008 22:25

Ah... then that's a good thing. That's a nice tight trans. On a windy day, I have to check the lever to be sure. And I've often gone to nuetral while running topside, then sat with the throttle at 1800 wondering why I'm not getting speed. D'oh! Embarassed

It's just the way of the single screw. If you want some feedback with every change in the trans, get a folding or feathering prop. Our old boat neighbor sistership had one (once Kyoga... not sure where she ended up) and it gave a solid "thump" when put in gear. Sadly their's was a 3 blade that was too much for their Atomic. If you put it in revers gear in idle it would kill the engine. Found that out while pulling into a strange slip, on a strange boat, with 30kts tailwind. Yikes!

sord · **Posted:** 06 Mar 2008 07:20

But surely I should be able to tell at the helm which gear I am in. Is the an adjustment or some thing that will let me know if I am in reverse, neutral or forward? When I come nice and slow into a slip I like to leave the engine running until all major lines are secure. To have the engine pulling the boat out while dock hands tie it up is difficult and embarrassing.

Tartan37.com

Transmission Problems

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