Quote Originally Posted by 98strat
You have to have something to communicate back with inorder for them to track you. Most aftermarket headunits with navigation or a stand alone like a Tomtom just use the signals they receive to calculate the position internally. They transmit nothing. As long as the truck does not have a hidden gps tracking system and just one only used for navigation for the driver it is highly unlikely that they are tracking you.
There is no hidden unit on it, I know what those are as Ive installed some before.