Transmission whine revisited...

[Captned]

Hello all, I tried to search past threads on this to no avail. Here goes - When I'm running the boat and shes all warmed up, I slow down and put the gears in neutral. When I go down to the cockpit, I hear this really HIGH pitched whine/ whistle and it comes and goes as we are bobbing around.... It goes away as soon as I put it in gear... Any Ideas? I don't think its caused by the props or the cutless bearings but....?

Cheers,

Captned
78 46 CON
Miami Beach

[Will]

What kind of transmissions do you have?
Will

[Captned]

What kind of transmissions do you have?
Will

Allison Transmissions.... With screw on remote filters... Could it be that packing gland that has never leaked???

[Genesis]

It may be normal. The Vickers pumps have a habit of producing a "whistle" noise, especially when out of gear. Its not the gear itself if its doing that - its the pump, and sometimes they do it, and sometimes they do not.

The reason is that there is a bypass/pressure regulator valve on the pump that controls the pressure output in the lines and the bleed through it sometimes makes noise.

[SKYCHENEY]

I had the same whining problem, but only in gear. It happened after rebuilding the forward clutch AND tuning the props. I couldn't figure it out. All we did was put new springs in to release the forward clutch (Allison M20) and depitch props. The noise was a high pitched whine from idle up to about 950rpm in forward gear. Above that it went away.

I lived with the whine for one whole season. Then I replaced all of my cutlass bearings AND switched the props to my spares. Problem solved. I have no idea what the cause was, but I suspect it was a singing prop.