yes..thats the weird thing. I don't know how servos work but no vibration when I do that maneuver..it runs noisely and smooth. Its as if once the motor gains momemtum and you quickly reengage it it either mechanically or electronically changes itself. You can only hear the machine working, not the motor..Isn't that the way they should be? It's the second motor since I thought the first defective so the motor isn't defective, maybe the design is..