Drove to Vegas from LA yesterday (with AC on full blast), parked in the stratosphere parking structure for about half hour, returned and as soon as I put it in reverse, there was this loud squealing sound and lots of vibrations coming from the front of the car. It lasted about 5 seconds before it went away, and it scared the shit outta me. It happened again after parking at another place. I immediately turned off the air conditioner and the sound instantly disappeared. I'm guessing something wrong with the AC obviously and it never happened before. My first problem with my 03 TL-S, after 83k miles. Anyone ever experience this or know what this could be? any help appreciated.

 

I have this sound sometimes too but I haven't taken it in to shop. Let me know what you find.

 

I get this sound, too, sometimes. It happens when I put the car from park to reverse. I don't think the AC was on though. Could this be a sign that the tranny is going bad?

 

Belt maybe?