I have a 2009 GL320. About a month ago we noticed that the rear of the car was low. We unlocked the doors and opened the rear right door. We could hear a noise. It was raising the car. I went to the shop they did a diagnostic scan which came back with no errors. He checked the air pressure and said it was good. We drove home. Now 34 days later the rear of the car was down again. Same thing happened, opened the door, the back end rose up. The next day everything was ok. I am not getting any messages on the message center. The vehicle has 80,000 miles on it. I am looking for advice on what might be happening and/or if this has ever happened to anyone else. The repair shop only tells me to bring the car back in and leave it with them until it happens again. That idea is costly and inconvenient. It's an hour away and I would have to rent a car. Thank you in advance for any help whatsoever.