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krward

Transmission Sounds Strange

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krward

OK another newbie question here. When I ran the slxi in the driveway yesterday I noticed a buzz/humming sound coming from the the transmission (or at least appeared to be). Checked the fluid, prop shaft alignment, loose bolts, screws, connections and etc to eliminate possibility of harmonic vibration.

When I put the boat in reverse the noise stops as it shifts into reverse and then starts again. Makes the same noise in neutral and in forward gear. It is not really loud or sound like something is horribly wrong, but just want to make sure. This is my first bu and I wondering if the sound is normal or something to be further investigated. With 149 hours and the fluid looking brand new can't image there is much of anything wrong.

Any thoughts or help is greatly appreciated.

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electricjohn

Your packing gland was dry, therefore you got a vibration. I bet your prop was spinning very slow in neutral too. good luck

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krward
Your packing gland was dry, therefore you got a vibration. I bet your prop was spinning very slow in neutral too. good luck

I 'attempted' to wet down the shaft and packing gland with some water prior to putting it in gear or the shaft makes a horrible sound because the strut is dry when it turns. So if I understand you correctly, would the sound stop briefly when the boat is put into gear and then resume once it is in gear?

Edited by krward

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SacRiverRat

You shouldn't put the boat in gear when out of the water...

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Lakenut

Don't put the boat into gear out of water. You WILL burn up your strut bearings.

It is normal for Malibu DDs to whine in reverse. This is a warning that you are going the wrong way. Biggrin.gif

Seriously, it will whine in reverse. Just the nature of the ZF Hurth tranny. Check your fluid level and get the boat in the water to test it out.

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NorCaliBu
You shouldn't put the boat in gear when out of the water...
Don't put the boat into gear out of water. You WILL burn up your strut bearings.
Fingerwag.gif Just to reiterate...Do not put the boat in gear when it's not in the water. Fingerwag.gif

:Doh:

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krward
You shouldn't put the boat in gear when out of the water...
Don't put the boat into gear out of water. You WILL burn up your strut bearings.
Fingerwag.gif Just to reiterate...Do not put the boat in gear when it's not in the water. Fingerwag.gif

:Doh:

Oops.gif Good to know. Point very well understood. Just for clarification, the sound is constant whether in neutral or in gear. Only stops for 1/2 second right when it shifts into gear then starts making the same sound as being in neutral. I am rather familiar with the whine it makes in reverse. This is definitely not that.

Called the service manager and he said wet everything down and put in gear and call him so I can describe what is going on. Seems like I should investigate finding a new service guy.

Edited by krward

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SacRiverRat

So the whining sound is being made w/ and w/out the prop turning?

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electricjohn

The prop will spin ever so slowly when you are in neutral, so look at your prop to be sure it is not turning. You can see the prop shaft behind the transmission too, where you can carefully grab it to stop the spinning (While in NEUTRAL). Wear gloves to be safe. This should stop the noise if it is coming from the gland or the strut.

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RTS

Could the whine be the trans pumping fluid up through the trans cooler. Maybe it goes away during shift out of neutral while valves are being opened/closed??? Maybe normal, or maybe a line to the cooler getting clogged a bit?

Could you give an idea of the "loudness" of the whine you are describing?

Edited by rts

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krward
Could the whine be the trans pumping fluid up through the trans cooler. Maybe it goes away during shift out of neutral while valves are being opened/closed??? Maybe normal, or maybe a line to the cooler getting clogged a bit?

Could you give an idea of the "loudness" of the whine you are describing?

I am going to pull the boat out again and run it in the driveway. I am not sure that it will work, but I will get my video camera and see if it will pick up the audio enough hear what I am talking about. Thanks for all the replies so far. It is raining today so I will probably not get something out there until tomorrow.

Edited by krward

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SmoothWaterMan

Please don't attempt to grab the prop while the engine is running.....even in neutral. You never know when it suddenly drops into gear -

Back to the subject - Before running it out of the water, take a short piece of 2x4 and place between one prop blade and the hull, with the blade in the direction of rotation. i.e.- the blade turns left, so rotate the prop so that it's holding the 2x4 against the hull. When you start the boat the static pressure of the fluid in the tranny will cause the propshaft to turn on a used boat (no resistance from strut bearings).

DO NOT ever put in gear with the 2x4 there, for you'll then need a new prop.

If the propshaft is not turning and the transmission is making noise, increase the RPM's to 750-1000 and see if it goes away. Often the dampener does not provide enough force to eliminate a little chatter at very low idle rpms (such as dead idle under way).

Of course, these are just ideas, without being there your service center may find something different.

Peter. :)

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krward
Please don't attempt to grab the prop while the engine is running.....even in neutral. You never know when it suddenly drops into gear -

Back to the subject - Before running it out of the water, take a short piece of 2x4 and place between one prop blade and the hull, with the blade in the direction of rotation. i.e.- the blade turns left, so rotate the prop so that it's holding the 2x4 against the hull. When you start the boat the static pressure of the fluid in the tranny will cause the propshaft to turn on a used boat (no resistance from strut bearings).

DO NOT ever put in gear with the 2x4 there, for you'll then need a new prop.

If the propshaft is not turning and the transmission is making noise, increase the RPM's to 750-1000 and see if it goes away. Often the dampener does not provide enough force to eliminate a little chatter at very low idle rpms (such as dead idle under way).

Of course, these are just ideas, without being there your service center may find something different.

Peter. :)

Thanks Peter. I will add your suggestions to the list of things to check. I went ahead and changed the fluid last night. Stuff I took out looked fine, but for $10 I spent to change it, figured it couldn't hurt. The joys of buying a used boat....It can drive you Crazy.gif

Thanks again to ALL for helping me out. This will probably turn out to be nothing and I am just being overly paranoid. However I don't want to find out in the middle of the season that there is a problem and then be stuck home watching the grass grow while I wait to get it fixed.

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Lakenut

So on a new boat the prop will not turn?

Mine doesn't turn in nuetral and I have 275 hours on mine.

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vlx wakesetter
Don't put the boat into gear out of water. You WILL burn up your strut bearings.

It is normal for Malibu DDs to whine in reverse. This is a warning that you are going the wrong way. Biggrin.gif

Seriously, it will whine in reverse. Just the nature of the ZF Hurth tranny. Check your fluid level and get the boat in the water to test it out.

Exactly never put a bu' in gear when it's out of the water. Why would you need too Crazy.gif

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krward

OK so it took forever for me to get to this. Got the boat out again today. No open water close by so I ran it in the driveway after changing tranny fluid. Same noise. This time did not put it in gear. However I happened put my hands on the two lines running from the transmission up to the transmission cooler. The humming/buzzing/vibration noise is coming from the fluid moving through these lines and I am absolutely positive that is where the noise is coming from as you could feel the vibration in the lines that was in sync with the sound. So that is my next question. Is this something normal to hear the fluid being pumped up through the lines or something I need to further investigate?

Edited by krward

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WaveMake'nLSV

Dunno...probably normal. Anyone think it might be a bearing/wear issue? Are there bearings in the tranny pump? And with the boat's age? Bout all I can think it could be, if it is anything

Dontknow.gif

OK so it took forever for me to get to this. Got the boat out again today. No open water close by so I ran it in the driveway after changing tranny fluid. Same noise. This time did not put it in gear. However I happened put my hands on the two lines running from the transmission up to the transmission cooler. The humming/buzzing/vibration noise is coming from the fluid moving through these lines and I am absolutely positive that is where the noise is coming from as you could feel the vibration in the lines that was in sync with the sound. So that is my next question. Is this something normal to hear the fluid being pumped up through the lines or something I need to further investigate?

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mrothwell
OK so it took forever for me to get to this. Got the boat out again today. No open water close by so I ran it in the driveway after changing tranny fluid. Same noise. This time did not put it in gear. However I happened put my hands on the two lines running from the transmission up to the transmission cooler. The humming/buzzing/vibration noise is coming from the fluid moving through these lines and I am absolutely positive that is where the noise is coming from as you could feel the vibration in the lines that was in sync with the sound. So that is my next question. Is this something normal to hear the fluid being pumped up through the lines or something I need to further investigate?

Here's a guess. Maybe the noise is coming from air in the lines. If you are using a fake-a-lake, air can easily be introduced into the system. I could see where this could cause noise. I would drop it in the lake, and then see if the noise goes away once all the air pockets get evacuated.

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krward
Here's a guess. Maybe the noise is coming from air in the lines. If you are using a fake-a-lake, air can easily be introduced into the system. I could see where this could cause noise. I would drop it in the lake, and then see if the noise goes away once all the air pockets get evacuated.

Just need to find a lake close by without ice on it Mad.gif . That will be the next thing I check. Any chance you think that it could be cause by a blockage in the cooling lines or the screen in the transmission? Not sure how that would happen, but it is a used boat.

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RTS

Is the noise more pronounced at the transmission or at the trans cooler. If it's louder at the cooler, it very well could be a "lack" of water trough the cooler. A garden hose and fak-a-lake generally won't provide the amount of water being in the lake will.

I hook my hose directly to the impeller intake (I hand made a special device for this :) ) and even at idle with the hose open full, the suction tries to collapse my garden hose. I'd assume you'd have some leakage through the fak-a-lak, so you'd be getting even less.

Maybe try this. Get a 5 gallon bucket, fill it with water, remove the raw water intake from the thru hull connection and stick it in the bucket. That will provide more water through the cooler. See if that makes the noise go away (assuming the noise is louder at the cooler)

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krward
Is the noise more pronounced at the transmission or at the trans cooler. If it's louder at the cooler, it very well could be a "lack" of water trough the cooler. A garden hose and fak-a-lake generally won't provide the amount of water being in the lake will.

I hook my hose directly to the impeller intake (I hand made a special device for this :) ) and even at idle with the hose open full, the suction tries to collapse my garden hose. I'd assume you'd have some leakage through the fak-a-lak, so you'd be getting even less.

Maybe try this. Get a 5 gallon bucket, fill it with water, remove the raw water intake from the thru hull connection and stick it in the bucket. That will provide more water through the cooler. See if that makes the noise go away (assuming the noise is louder at the cooler)

Any chance you would be willing to post a pic of your 'hand made device'? I have been considering doing this, but could use some ideas. My idea is to just put in a tee connected to some kind of valve (that you can close) that has a female garden hose connection to hook up the hose to.

Edited by krward

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RTS

I'll get you a picture this evening

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RTS

krward,

Here's what I made to provide water to the engine during maintenance. Crude but effective and only a few bucks in parts. I just connect it straight to the intake of the impeller. The valve lets me start/stop water without having to get out of the boat, and the clear tubing allows me to confirm water flow.

post-58-1173917825_thumb.jpg

Edited by rts

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krward
krward,

Here's what I made to provide water to the engine during maintenance. Crude but effective and only a few bucks in parts. I just connect it straight to the intake of the impeller. The valve lets me start/stop water without having to get out of the boat, and the clear tubing allows me to confirm water flow.

Crude? Not to me. Just a good idea. I was taking it way too far thinking about creating my version of a perko flush kit. I like your idea much better. I never run my boat in salt water so the flush kit is over kill. But disconnecting the raw water intake and hooking this up is much cheaper and a less complicated way. My guess is this takes less time than dragging the hose and the fake a lake under the boat and getting it setup then running back and forth turning on and off the water. Thanks again.

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VinRLX

Be sure to prime the intake line prior to starting the boat, the impeller will likely not pull the water from a bucket otherwise.

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