So I managed to open up the device.
As I stated before, it was the antenna that was loose.
Nothing is holding it up in place so it was rattling in the case.
I just glued it up, problem solve.
I think that you engineer should have known right away that the problem was the antenna.
I told you that it was rattling "at the top of the device", which is where the antenna is.
Opening the case is quite easy, I will redo the silicone joint and close it back up.
Having the antenna rattling like that will, without a doubt, damage the antenna in the long run, so this is a mandatory fix
in my opinion.
It is an easy fix and it could prevent other customer to loose there device in the "shippping back for warranty" black hole.
Not mention that, only in this forum thread, we are 3 customers to report this issue, so this should ba a concern.
Having said that, I am still very please with the GPS device!
Attached are the picture where it shows the loose antenna, where I applied some glue and where you have to open up the device.
There is no screws, just a silicon joint
I hope this can help someone else !