Noise coming from the transmission

I’m wondering if you can give me some quick advice so I don’t get carried away. I have a ’76 Atomic 4 with a direct drive transmission on my Islander 28. My Cutless bearing is admittedly quite worn- about .040 of slop, but this past year I noticed what sounded like bearing noise coming from the transmission. It was most noticeable at cruising rpm. When I did the breaker bar against the ear trick for pinpointing noise source, I did not hear anything alarming or outstanding. There is no telltale oil fling from the rear seal either. I suppose it could be only the cutless, and how the hull picks up the vibration. I will replace that this spring, but I was wondering how I might investigate the health of the thrust bearing and other bearings in the housing. Can I determine anything if I disconnect the shaft flange? Universal’s exploded views of the transmission are a bit blurry, so I don’t really have a good mental image of what is going on.

I’d rather not get into a rebuild now, as I use the engine infrequently, but I don’t want it to self destruct either.

Can you offer any words of advice?

[Don Moyer]

I would grab the prop shaft and try to move it laterally or up and down to determine whether or not the thrust bearing has any noticeable play. If there is no play in the thrust bearing, I wouldn’t replace it until replacing the cutlass bearing.

Separating the prop shaft from the engine coupling may give you a little better feel to check the bearing for play.

Regards,

Don