I actually called Freightliner, with my VIN, they said the only buzzer was the loud one used by the low air warning....
It appeared, at first, that the order in which I released parking brake, etc made a difference.....not anymore...
Usually we can start driving, with no buzzer/beeper, than after an indeterminate period of time the sound starts... sometimes it will stop on its own, sometimes not... sometimes for a short while, sometimes for miles and miles... sometimes the sound is louder than others.....