It is not the outer assembly that wiggles at driving speeds it's the glass itself.
the mirrors move or flutter up and down like someone was flipping the mirror adjust switch really fast.

Even though the outer assembly on the driver side is loose I will try your advice to tighten it up. the mechanic could not see a way to adjust the gear assembly to get the outer assembly to self tighten.
I must admit he almost gave me a heart attack when he had folded the mirror assembly in and out by hand.