Hello, the rear triangular window exterior plastic window trim on my 1993 240 is vibrating at highway speeds. I'm not sure how the plastic window trim plate is attached to the glass or frame. This is the small triangular rear window, not the main window. There is a small rivet but no screws to tighten on the trim. Does anybody know how to secure and tighten the plastic trim? It appears hollow underneath, so was there some kind of adhesive or filler to hold it in place? Thanks!