Alpha One gen2 gimbal bearing failure?

[dlogvine]

I took my 1998 Ebbtide Campione with 5.0L Mercruiser and Alpha one gen2 outdrive. At first there was some unusual rumbling noise but not very loud when I started the engine, but it subsided when I got to higher rpms and until an hour later the engine was running fine. Part of this time we were in a no wake zone when we had to go on low gear and the engine was running on about 2000rpms. When we left the no wake zone in the canyon I shifted the throttle to high gear and heard a distinct rumbling noise with some knocking that was coming from the rear of the engine around the transom. I stopped and checked the outdrive. Propeller was spinning freely without any noises or difficulties. On neutral the engine was also running very smoothly without noises. So I had to return back to the dock on low speed, going around 3-5 knots at 2000 or below rpms. When i was making a turn the noise increased but not by much and I did not dare to try it on the higher rpms fearing the destruction of the gimbal bearing, which was my immediate suspect. I replaced it last year when I was changing bellows rubber, but stupid me, I bought a Chinese chip crap. Also when I took out the old bearing it was just fine and was spinning freely. I still have it oiled and sitting in my drawer.
I have 2 questions, 1 one is about the suspect in gimbal bearing, could it be anything else and if it is a bearing, what kind of damage could this failure have caused to the outdrive shift or the coupler.
​​​​​2nd question, im going to replace the bearing or at least take it out and look at it. So should I at the same time replace Ujoint bellows (that is the only Chinese rubber that I put, the rest was good quality Mercury bellows kit. This bellows is pretty good at my first inspection and could probably serve a couple years. Also is there an easy way to replace the bearing without taking the whole gimbal apart?
thank you.

 

[tpenfield]

Your boat has a low and high gear :noidea:

U-joints or gimbal bearing You won't know until you open things up and check. U-joints can 'feel' OK, but under load grumble and complain.

Take a look at the bellows . . . if it looks OK, you may be fine with it.

You'll also want to make sure the engine alignment is proper - with the alignment tool.

 

[Lou C]

Sounds like the bellows may have leaked and caused the bearing to fail, you’ll see when you pull the drive off.

 

[Bt Doctur]

water entry or improper installation is the cause of bearing failure. Bearing and tolerance ring are a unit, removed as a unit and installed as a unit.

 

[dlogvine]

Your boat has a low and high gear :noidea:.

Of course it does not have any gears, I meant adding more gas with a throttle. When I shifted the throttle lever to add more gas, that is what I tried to say.

I will start with checking out bellows and then the bearing.