whine when rolling off throttle

[Matt Chapter]

So I had the transmission rebuilt not that long ago, a few hundred miles, and I'm still sorta getting used to the noises it makes, but this seems unusual.  I haven't been riding much recently so I can't remember if it's been consistent since the rebuild or started recently.

When I roll off the throttle, I can feel a mild vibration and I hear a high pitched whine, kinda "whhhnnnn" until throttle is reapplied or the clutch lever is pulled in.  Suffice to say, I'm skeered.  I haven't talked to the shop that did the transmission work yet, but I'm also thinking it may be clutch rather than transmission related.

Any thoughts?

[montmil]

Mild vibration? Are you sure the new noise is coming from the gearbox?

Racket occurs only when the engine is not under load but disappears when throttled up. I would think timing chain except that 'vibration' item doesn't fit.

Perhaps the bearing in the clutch release mechanism? I'm guessing here...