I have the vibration in the driver mirror as well. It happens at any speed with the smallest bump. I recognized its depending on the position of the mirror. The farer you adjust it inside the lesser vibration you have. I need it very far out due to my 6'4.
I also see that it doesn't go smooth from inside to the outside. It got stock on 2/3 of the way as if the gears jumping over some teeth.
The passenger side is fine! Solid, smooth just great.
2012 Limited V6 4x4
Tow Package, Skid Plates, Tow Hooks, Tubular Side Steps, Mud Flaps, Underbody Protection
Planned: headlight washing system, amber rear blinker, rear fog light, change amber parking lights to whites, lockpick, front camera, swap RBZ to RHW