Thanks for sharing. Any pics of the repair?This^
My solution:
I made a shim out of a Costco Maple syrup bottle.
I used my Weiss snips. Heavy scissors would work. Careful if you use a razor knife.
Cut the bottom out ~3" diameter. Used a drinking glass to trace the circle.
Cut a hole inside this 3" circle, ~2" diameter. " " "
Cut about a 1/2" gap in this shim
Slip it into the offending gap
Use a trim tool or similar tool to fully insert the shim.
Fixed, no more shimmy and shake
Mirror folds and extends with no issue
Barely visible and if it bothers you, a black sharpie with fix it.
You could use a Rubbermaid lid for the material but I used enough kitchen stuff for my projects...I avoid the future conversation regarding "one of my lids is missing".
Any HDPE will work. I'd advise against rubber. To much friction...you want plastic on plastic.
Hope this helps until Toyota admits it's a problem and offers a solution. Dealers will just look at you and likely state "they all do it; it's normal".