I had the same issue, in the beginning it was barely audible but it got louder over time. I found out there are two kinds of noise generated by the oscillating mechanism. One is a very quiet click that appears at each, or just one end position of the turning cycle. This is due to the tolerances in the oscillating mechanism and can not be solved without replacing or modifying parts of the mechanism. The other noise I noticed, did not happen at an end position and it was more like a rattle/ series of clicks, almost a silent squeak. In my case, this seemed to be coming from the cable connecting the motor with the mainboard. While the base plate and the motor moves against each other, the cable bends and may touch the housing or other parts. Also, there is a plastic clamp, holding the cable in place on the mainboard. I used just a few drips of silicone spray to lubricate the cable and reduce the friction on certain points. It is now absolutely quiet!