Sounds like air brakes on the drivers rear

[1flynDO]

Just like it says. It has happened twice so far. Really weird sound. Any guesses?

Thanks

 

[umbertob]

Do you hear it a few seconds after you park, exit the car and close the door? A brief release of air from the electronic air suspensions is normal, as the rear end often levels.

 

[1flynDO]

Nope heard it driving at highway speeds while braking