I pretty much have the same problem, but I would define the noise as more of a grind. I have diagnosed it to be the coupler. $30 part from rollingperformance.com
Requires taking the SC off the block, and taking the nose drive off the SC. Not hard to do.
Basically the shaft and the actual rotors are connected by a coupler. This coupler has holes in it. Over time these holes wear into more of an oval shape. This oval shape creates that "slop" you feel and can cause noise.