At the moment it shifts from 1 to 2 there is a slight rattle that comes from the tranny. It does not make the noise on light acceleration. It does it only when it is moderate (or more) acceleration. It is only there for about 1/2 second, but it is there and unmistakable. It kind of sounds like when you are trying to open a childproof bottle of something without pressing down on the lid hard enough. You know that click-click-click sound (but faster)? I doubt I could capture it on a recording.