rakkus

[Rakkus]

Hello. I have a 1998 40 DA. The boat is powered by twin 454 Magnums rated @ 380 HP each. When I engage reverse on the port engine there is a meshing sound. (similar to sound produced in YouTube video seen in the link) I have had the trans fluid analyzed with negative results for metal contamination. There are no leaks in the trans fluid unit or the trans fluid cooler. I am told this is "low idle engine chatter" common in older model boats.   Can anyone give me more information on this issue. 

https://www.youtube.com/watch?v=GoBRnlRPB9Y

[wingless]

It doesn't sound like the vee drive clatter on my transmission.

Could that be noise from the shaft seal?

Assuming dripless seal, has the supply been tested for sufficient flow and has the seal been tested for unobstructed backflow, per the manufacturer's instructions?

[Rakkus]

Thank you for your advise. yes, they r dripless. will examine & advise.

[BWLF]

Try upping the rpm when engaged in reverse. If chatter goes away then it is just low rpm chatter. Very common in late 90 models.