Hi, I found a lot of drive oil inside my bellows so i brought my drive to a merc mechanic. He said it was the seal and he replaced it. He also replaced the u joints since the drive was off the boat anyway. Yesterday i started the boat up on a hose and noticed a rattling sound that i never heard before coming from the upper housing area. After doing some research i noticed that there is a procedure to adjust the rolling preload on the bearings.. If the preload was incorrect can it make a noise like this?
what else could it be?
note. Drive is spinning in gear looks like it is just rocking back and fourth..not the case just shows that way in video

https://www.youtube.com/watch?v=au6xujfCaOk

https://www.youtube.com/watch?v=jWcaYPjrQBU

Geez, sorry I don't have the answer but any noise from the drive is normally not good. Did you tell the Merc Mechanic about it? That would have been my first call.

He checked it out and said it sounds like a u joint because it got louder when turning the steering. We removed the drive and one u joint was binding a bid tight... Hopefully that was it

Your prop in the first vid is rocking back n forth, this would have me think the gears were not timed and its slipping between FWD/REV

Noticed that too...that shouldn't happen under any circumstance.

Something is wrong inside the drive. The U joints wouldn't make any noise with the drive level to the hull.
You did refill the drive with oil right.
If the noise gets louder when you turn the drive it is probably because you are side loading the input shaft.
I bet the input shaft bearings are bad.

The drive in the video was in gear...The prop is spinning...I found the video strange also showing that...looks like it is rocking...not the case here

never had a noise in that drive before the seal was changed...It was quieter with the oil seal leak

There is a u joint that seems tighter than the other, that's being changed today ..oil level was where it supposed to be.. filled with Amsoil marine drive gear lube..(great stuff)..input bearings bad? or not put back together correctly??

My drive has an OF starting part of the serial#. It is back from 2003 year I believe 2nd gen. How do you know if the input shaft bearing pre-load is 5lbs rolling or just tighten to 80 lbs torque..Is there a way of telling?