Bd -- you may be right about the horizontal bearing being sluggish. Possibly from spilled silicon damping fluid like you said, or maybe just dried out lubricant. Test the horizontal swing at zero VTF and NOT on the cuing support. Use a stylus guard to protect the stylus.
Another thing to check is that the tonearm connecting wires are not inhibiting the arm movement. There's tons of info about the PT6 including upgrades. Just go to Google and type "Audioquest PT6" in the search field.
Another thing to check is that the tonearm connecting wires are not inhibiting the arm movement. There's tons of info about the PT6 including upgrades. Just go to Google and type "Audioquest PT6" in the search field.