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  #1  
Old 06-25-2008, 08:54 AM
Skipper
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Clunky Transmission in Neutral

The issue:
In neutral, at idle, the transmission produces some clunking noises and the shaft spins very slowly. No problem shifting, accelerating, holding speed, or decelerating.

The boat:
1995 Prostar 197, standard EFI engine, 1:1 transmission, 520 hrs.

I suspect I am in need of a rebuild. My previous experience is limited to Velvet Drive transmissions. Any ideas?
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  #2  
Old 06-25-2008, 09:40 AM
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trickskier trickskier is offline
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Does your shaft have a keyway in it?
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Old 06-25-2008, 10:40 AM
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Originally Posted by trickskier View Post
Does your shaft have a keyway in it?

Yes, no issues with the driveshaft from prop to coupling.
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  #4  
Old 06-25-2008, 03:48 PM
Hunterb Hunterb is offline
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The slow spinning shaft is fairly common and not necessarily a sign of a transmission problem. The clunking may be your damper plate. It's the thing that goes between the flywheel and the transmission and it has a number of springs etc. in it. They are inclined to make funny noises at idle sometimes. Unfortunately you have to remove the tranny to check it. I would look very closely at that before I had the tranny re-built.

Bruce
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1990 Prostar 190, 351 Indmar SO, bought as an empty shell and rebuilt over the winter (04/05). Sold in May 2009

New boat - 1993 Prostar 205. Bought in better shape than the 190 was but still needed some work.
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  #5  
Old 06-25-2008, 04:15 PM
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kawagaskier kawagaskier is offline
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It only does this in neutral? I had a similar problem with my 85 S&S, but in gear at idle. Turned out my idle speed was a little low. I adjusted the idle up to about 750rpm and the clunk was gone.
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Old 06-25-2008, 04:52 PM
Much2do Much2do is offline
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Is the clunk heard when you shift into gear or while you at idle idle out of gear?

If it's simply an excessive clunk shifting into gear then replacing your transmission fluid may solve it.
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Old 06-25-2008, 04:56 PM
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Quote:
Originally Posted by Angry_Bill View Post
Yes, no issues with the driveshaft from prop to coupling.
If it's making a ticking noise, then the keyway is going bad. My 82' had this same problem and the driveshaft finally came out hitting the rudder and damaging the prop........I had to replace the shaft & the prop.

Pull the shaft and inspect the keyway area.
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Old 06-26-2008, 06:28 AM
Skipper
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Quote:
Originally Posted by kawagaskier View Post
It only does this in neutral? I had a similar problem with my 85 S&S, but in gear at idle. Turned out my idle speed was a little low. I adjusted the idle up to about 750rpm and the clunk was gone.

Not an idle issue, in fact the idle is a little high.
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Old 06-26-2008, 06:29 AM
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Originally Posted by Much2do View Post
Is the clunk heard when you shift into gear or while you at idle idle out of gear?

If it's simply an excessive clunk shifting into gear then replacing your transmission fluid may solve it.
Not really making a clunk when I shift. The shift is just fine. It is just that when the engine is idling there is excessive clunking or rattling noise coming from the transmission. I change the engine oil and transmission fluid every 25 hrs.
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Old 06-26-2008, 06:31 AM
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Quote:
Originally Posted by trickskier View Post
If it's making a ticking noise, then the keyway is going bad. My 82' had this same problem and the driveshaft finally came out hitting the rudder and damaging the prop........I had to replace the shaft & the prop.

Pull the shaft and inspect the keyway area.
Not really a ticking noise.
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