Loud rotation/grinding sound. u-joints and gimbal are like new?

[RCSConstruction]

I have a 2004 Caravelle with a 4.3gl/sx-m drive. I bought it from a guy who let it sit for 3 years with only 59 hours on the whole boat. Everything looks like new. (I replaced all exhaust, and all maintenance stuff)
When I have the drive on muffs and turn to the starboard side it has a bad rumble, rotation noise, not so much port side but still there. I figured I had a bad gimbal or u-joint but I pulled the drive and they look brand new! Not one spec of dirt/rust, nothing. The bearing is smooth as butter as well as u-joints..
Alignment tool shows splines all the way around, so it's aligned. Maybe a tad heavier on the bottom than the top, but not enough to worry I would think.
Is this a case where the gimbal is only bad after a certain rpm? It's only pronounced at 1800rpm and above, but you can slightly hear it at idle.
Could it be a bearing in the upper unit? Doesn't seem that way since it's steering related but what do I know.
Any thoughts are appreciated!

 

[tpenfield]

Is the drive trimmed down into the normal operating range when you are running it on the muffs?

 

[RCSConstruction]

Is the drive trimmed down into the normal operating range when you are running it on the muffs?

Yes. Not quite all the way because my skeg hits the pavment but well into in the "trim zone".

 

[BRICH1260]

Do you have greaseable Ujoints and gimble? If so, maybe give them a few pumps of new grease.

 

[RCSConstruction]

U-joints are not greaseable, I did grease gimbal heavily.

 

[BRICH1260]

Another suggestion. If it sat for three years, make sure you replace the oil and check it for contamination, then refill to the proper level.

 

[RCSConstruction]

Another suggestion. If it sat for three years, make sure you replace the oil and check it for contamination, then refill to the proper level.

Oil looks brand new. I put it in drive to get the oil moving around to see if it got milky, but nothing. I was hoping to run the boat hard then change all fluids.

 

[89retta]

Take it out on the water. And see if the noise is still there or goes away.

 

[RCSConstruction]

Take it out on the water. And see if the noise is still there or goes away.

Too late now! took the gimbal out.. haha
It really feels brand new too.. Can't get any play out of any u-joints either..
Guess I will take her out and see what I got..

BTW--looks like we have identical boats, right down to the color. I've never seen it in the water like your pic. Does the rear platform ever dig into the water when trying to get on plane?

 

[89retta]

I don't think the platform digs in. Gets on plane pretty quick.