Borg-Warner Velvet Drive Knocking

[Luke]

I've got an Isuzu Pisces 4 cylinder mated to a velvet drive in my CT-41. The engine purrs at idle, but when I engage the tranny it starts knocking (not the engine - the tranny.). It sounds like it's coming from inside the transmission (reduction?) housing.

There is a loose bolt on the nylon coupling, but I can't get it on a thread, and it doesn't seem to be the source of the sound. How do I check driveline alignment - is it obvious?

Also, the transmission housing has a lot of surface rust, while the engine is clean. Is there a zinc for this?

Also, I thought reverse had it's own separate gear oil from the ATF in the tranny, but I can find no dipstick for that.

Thanks in advance for any help/advice...

[GordMay]

Greetings and welcome aboard the CF, Luke.

Some Velvet Drive Service Manuals

➥ http://www.kp44.org/ftp/VelvetDriveServiceManual.pdf

➥ http://www.velvetdrive.com/techinfo/...ertyowners.pdf

➥ http://www.mv-dreamer.com/VelvetDriveOwnersManual.pdf

➥ http://www.perry47.com/transmission/...structions.pdf

Previous CF discussion
➥ http://www.cruisersforum.com/forums/...oise-8919.html

[AnchorageGuy]

Luke, we had the same transmission on both our Perkins and Yanmar for about 17 years. Every time we put the transmission in gear at idle it sounded like it was full of rocks rolling around. That transmission is still on the boat with the current owner almost 20 years later and still works perfectly and has never failed. I am not sure if this might be what you are referring to or not. If you are concerned you should have someone experienced with that transmission to look at it. It is hard to hear it on a discussion board. Good luck, Chuck

[Chief Engineer]

can o'rocks?

Dampner Plate

[AnchorageGuy]

Originally Posted by Chief Engineer

can o'rocks?

Dampner Plate

Not true since it continued after we repowered with a Yanmar, put in a new damper plate even though the old one showed no signs of problems, and the sound remained the same. Chuck

[Chief Engineer]

Wasn't referring to your boat...referring to OP

[AnchorageGuy]

Originally Posted by Chief Engineer

Wasn't referring to your boat...referring to OP

Sorry about that Chief. Chuck

[neilpride]

I have in my Perkins a borg warner trany, and he never made any strange noise at idle or full rpm, so, yeah !! i agree with chieff, Damper plate is suspicious,,,

[jenny2]

My C70 would rattle like crazy when idling when I got home and repowered the springs were bout to fall out of the Damper plate the gear was rebuilt with a new Damper plate also no noise now