Drivetrain Noise

[aviatorg3]

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.

[jeffery s bennett]

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

[aviatorg3]

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.

[aviatorg3]

Just one side. Never made that sound last year.

[jeffery s bennett]

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

[aviatorg3]

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?

[jeffery s bennett]

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

[birdog]

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

[aviatorg3]

what Exactly is that, and how hard to replace?

[birdog]

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.