i think i see the problem, it looks like someone installed a couple radishes instead of bearings
wipe the grease out of the tulip and look at the ball wear path, if its like some youll find a fairly hard endge/ridge at the end of the worn area....this is what leads to vibrations when a motor mount is replaced or any work is done....those balls no longer ride in their original path and can end up bumping up the ledge which from the drivers seat will feel like a vibration as the ball rolls up the slop/ridge and then back down