I have a new Walkera G3D gimbal but the correct answer I'm looking for will apply to all like gimbals. I have only had a few flights so far and they are a bit better than my 2 axis Walkera. Yesterday morning I get ready to fly. Power up gimbal and after some seconds it straightens out as normal. Then I notice a noise like a cd rom disc spinning and the gimbal had a vibration to it you could feel if you touched it. This would happen for about five seconds and then stop and seconds later start again. I went to fly and before starting rotors, I could hear the sound along with the vibration in the video. Other than that the gimbal worked normally. This morning I power up the gimbal. No noise, no sound, still as can be. Is the gyro on the back of camera mount actually spinning inside? It sure sounded like it. This morn although very quiet and still, I can hear something if I put my ear real close.