Just curious if any of you OE guys have experienced the following.

Installed rebuilt motor. Engine running in neutral, everythings good. Put in gear and feel and hear a grumbling/thumping/knocking noise. I adjusted scatter shield to clear drive shaft. Replaced U-joints on drive shaft. Still noise. Removed drive shaft, put in gear, no noise. That would eliminate tranny. Swapped driveshafts no difference. Hand rotate prop which rotates ASD-1600. don't feel any grinding, binding etc. Any help or suggestions would gratly be appreciated.

my borg warner trans with my arnesons make a lot of racket at very low idle speed specially in reverse. Is it just one side? The guy who built mine said it is normal. I have stood in the bilge of a big cruiser with quiet engines and they do make a lot of noise at very slow speed
Jeff

The transmissions make no noise when the drive shaft is removed and I put them in gear. I would think that this would eliminate the transmission as the source of noise/thumping.

Just one side. Never made that sound last year.

have you checked the flex plate for broken springs? I had one come apart years ago, made some funky racket. I only found it when i had an unidentifiable spring in the bilge

Haven't checked it. I know the springs are not missing. But wouldn't it make the noise with the drive shaft removed and the transmission in gear?

i do not think that it would since there is no load on the drivetrain without the shaft/drive???

Sounds just like mine...ssmVs----Carrier bearing fixed mine

what Exactly is that, and how hard to replace?

Its the bearing that the yoke spins on...Exiting the boat
Mine is in my extention boxes.

We pulled the motor to make it easier but, You might not have to.