The first thing above the swash is the lower rotor head. It is attached to the swash thru linkages that should keep them together unless your swash is separated, in which case, part of the swash will rise up, mkaing it look like the lower rotor head is moving. The next thing above the swash is the inner shaft bearing holder. If it is bent or loose, it may cause shudder, but a more likely cause is a bent shaft. Read Soloboss's article on the CX2, study the CX2 diagram in your manual, and systematically take your CX2 apart until you find all of its bent and broken bits. You will learn from the experience and your CX2 will fly better than new.