The big oversized street sign killer mirrors are always shaking. If they don't shake at the joint they will shake at the housing or even the mirror it's self. I have had problems with the mirrors distorting the image. First the joint where they fold in began to loosen. I told the dealer and thought they were going to just tighten. Well they changed the entire assy. The only problem with that is the one they put on was worse. The mirror itself moves around in the housing. You can't see anything while moving. I even had an entire mirror housing come loose and almost fall off. With the size of these things, they could kill somebody. It was hard to notice because the mirror was already moving around a good bit. You have to really look at it and the black housing to determine which one is loose.