Took a nice day trip up to the top of Palomar Mt. along Palomar Divide road yesterday. This isn't an off-road park or anything - it has some dirt trail, broken asphalt road and tight areas that might not work for a car, but most trucks or SUVs could deal with. I never got out of high rang or anything like that.

About half way up, 6 or so miles, I started hearing a high pitched intermittent squeal that I thought was the radio at first but was still there after turning it off. My wife noticed it too. Performance was normal, and I don't remember it making the noise with the brakes applied.
After a 60 minute lunch at the end of the trail (cool fire look out tower, if you are in SoCal and looking for a nice day trip.) we headed back down and never heard the squeal again.

So, what was it? Rock stuck in the brake pad dragging against a rotor? The road was significantly rougher that normal streets, so it's possible something was shook loose, but I would think it would still be making the noise if that was the case.

Just checking in to see if anyone has a similar experience.

 

If your GX has power 3rd row seats it may be that they are not positioned
fully down or fully upright. The warning sound for that is persistent and does
not go away until you correct the situation.

 

I know that noise, it's not that. This was higher pitched, and coming from outside the car. Thanks for the suggestion, though.

 

Yeah... might have just been a small rock wedged between the rotor and backing plate.