[Alex00]

I have Shake reduction turned off when i'm taken long exposures on a tripod, but, During the shot while mirror is exposed, if i get my ear close to the camera, i can still hear some noise coming from the camera. Since shake reduction is turned off, i'm wondering what this is noise is all about.

[sterretje]

I'm not sure about it but the following sounds like a sensible explanation.

I think it is the SR mechanism. The sensor is free floating and still needs to be held in place; else it would go down to the bottom due to gravity. That might be the sound that you hear.

[Gimbal]

You are correct, the SR voice coil motors holds the sensor in position even if SR isn't used.