Topeteomar

Hi I was wondering if anyone else has had the same problem as I am having right now.. My 2005 f150 v6 started to shake while driving when I'm going 25-35 and 65-75 mph and the worst problem is when I try to turn off my truck it shake really bad before its off.. Any ideas to what it can be? There is no check engine light on.. I have also takin my truck into 3 different shops including Ford and they can't tell me what it is...