You're talking about the U-joint, I think. The OEM one is a HORRIBLE, flimsy, stamped-steel piece. I replaced mine with this die-cast U-joint from McMaster-Carr, part number 6445K3. (
www.mcmaster.com) You'll need to drill two holes, one in each side of the U-joint so you can attach it to the rotator shafts with either roll pins (what I eventually added to the one pictured) or cotter keys.