Transmission sounds like marbles......

[HLCII]

We took our boat out the other night and came in limping on one engine. The boat was upgraded with 2005 Mercruiser 8.1's in 2005. At that time, the transmissions were also changed out, along with addition of dripless shaft logs. Everything was fine, then we noticed we were loosing RPM's on the starboard engine. The engine died, and would not stay cracked. We go the boat into the dock on one engine and raised the engine cover. We cranked the engine again, engaged the transmission and it sounded like it was full of marbles. The next day, cranked the engine, engaged the transmission and it is quite as ever, no issues. Of course I'm afraid to take it out.... I am wondering if I have a bearing going bad and it only makes a noise when it gets hot... Any opinions out there???

 

[kevin27]

When was the last time the spark plugs were changed?

 

[Xplicitlnck]

I recently had a very similar issue but never lost rpm as your describing. this HTML class. Value is http://clubsearay.co
I don't know why I can't get the link to my thread but if u look at my recent started threads it's called velvet drive noise. But to sum up the thread, do a tune up (spark plugs wires rotor) and the noise will go away. (No promises but everybody says it anyways works) basically if your engine is running rough your trans will make noise.

 

[northern]

My transmission are old and they sound like that at idle, was told it is the plates vibrating. New ones was told they have a rubber spacer system between plates. I change the transmission fluid every 2 years. It looks clean, no burnt smell and not down.

 

[Xplicitlnck]

Oh yes the dampener plate is also known to drop springs as described above. If you get a decently loader clunk sound when engaging one trans into gear then the other it's a warn dampener plate but being yours is new in 05 I doubt it

 

[HLCII]

Thanks all for your responses. The engine sounds fine. Tonight I decided to put the transmission in gear while in the slip to see if running it for a while might create the problem....and it did. Within a couple of minutes the transmission started making the same noise and shutdown the engine....I'm at a loss.

 

[Xplicitlnck]

Thanks all for your responses. The engine sounds fine. Tonight I decided to put the transmission in gear while in the slip to see if running it for a while might create the problem....and it did. Within a couple of minutes the transmission started making the same noise and shutdown the engine....I'm at a loss.

What kind of transmissions are they? Did you find my thread?
http://clubsearay.com/showthread.php/74007-velvet-drive-noise
Ha got it.
Anyway. Try this. First check your idle rpm numbers. If there on the lower side about 600 rpm the noise will be present. Bump the throttle up to about 7 800 and c if the sound persists. There's a couple guys that responded to my same question about marbles in the trans and they all said they changed there plugs and it went away. From what I hear the 8.1 is notorious for eating spark plugs and just because everything sounds like it's running smooth, just a little bit of roughness will cause this sound. Another thing to check is your trans fluid. I also had a heat exchanger fail and filled my trans with water. I caught it in time so no harm done but just another option

 

[julietbravomike]

I agree with what's said here, there are numerous instances of v-drives rattling at low idle and/or when there's an ignition issue such as plugs, wires, cap, rotor. You can have a miss on one cylinder and it's hard to tell any real difference in how the engine sounds. Don't jump to an expensive conclusion without ruling out these first couple of options. Good luck!

 

[Air O'Nautical]

Your engine has the ability to "sound" OK, even if it's missing a whole cylinder at times.
It's most likely NOT the tranny but, as suggested the engine's ignition system.
Check the spark plugs and wires first.

Neat way to learn what an ignition miss in your boat sound like...

Try looking at the good engine that's not giving you any problem.
Start it and warm to normal operating temp.
Now, pull a random plug wire off the plug and set it away from any possible metal it could spark to..(we don't want any exposed sparks in the ER).
Restart the engine and put it in FWD....now try REV.....hear the marbles..?

 

[HLCII]

Thanks again all. Sounds plausible, I just don't understand why it sounds and runs fine when cold, but after running the transmission in the slip (in forward) it takes about 3 minutes and sounds like something loose rolling around then kills the engine....

I'm now also wondering if the transmission fluid water cooler has possibly failed. Would that make it sound okay when cold, but as it gets hot fail and kill the engine??

 

[Alegria]

Just been casually following your thread.

While the advice you have been given is good I question how the conditions being described relate to the engine stopping.

Most questions of this nature that have been posted don't have that related condition. You may hear marbles but the engine should still idle and engage gears. It shouldn't stop the engine

You may have another issue related to your transmission.

Best of luck!

Sent from my AT&T LG3

 

[julietbravomike]

Thanks again all. Sounds plausible, I just don't understand why it sounds and runs fine when cold, but after running the transmission in the slip (in forward) it takes about 3 minutes and sounds like something loose rolling around then kills the engine....

I'm now also wondering if the transmission fluid water cooler has possibly failed. Would that make it sound okay when cold, but as it gets hot fail and kill the engine??

It sounds to me like your engine is loading up while sitting at idle in gear, so the rpm's start to drop, you get the characteristic rattling, then the engine dies. That sequence is something I'd expect to occur if you need a tune up. The transmission isn't going to get hot sitting in gear for a few minutes at idle. If you had a mechanical issue that serious it wouldn't be intermittent, you'd hear rumbling all the time. You can confirm the cooler issue by checking your fluid - if it's milky, then you have a leak - if the fluid has mysteriously disappeared (as in can't be found in the bilge) then you probably have a leak - otherwise, no.

 

[rondds]

Have you checked the transmission fluid? Cloudy? Low level? Any left in there?