Picked it up from fedex and drove for about two hours in my bumpy truck. The mount was moving around like crazy so I think it is a fair test. There is no way it is coming loose. I gave it a couple of good tugs before I attached it to the arm. I had the standard battery in and no case. I wish now I had bought the stardard sena case instead of extended as this mount will be keeping my axim juiced up all day.
Not to insult you but you did notice the button the extends the arms out all the way then you sqeeze them tight on the axim? I first slid it in until I saw the button and gave it a hard press, until then I thought I had the same problem as you. If not you diffently have a defective unit.
BTW- I could not believe how easy the setup was. I had MS streets and trips and iguidance already loaded so I set up everything (including the mount)in the parking lot and the gps unit was functional right away. No drivers or anything from the install disk loaded. I am going to read up tonight and do a proper pairing.