[Bob Kontak]

The rack passes through the assembly and is connected to the spindles via a tie rod on each end.

There is an inner and outer tie rod on each side. There is nothing else that moves unless the rack is flopping around in the steering rack tube or perhaps if the rack assy is loose in the car.

The boot covers the inner tie rod coupling to the rack. I would look at that connection under the boot on the right side. Believe that will help identify the movement source.