Does the gauge show charging on moderate braking and discharging under moderate accell? If it is then look and see what its doing when the noise is present.

 

another thing to look at is the rubber on the wind shield at the bottom, my 05 was making a noise at higher speeds and thats what it was, the rubber would start to vibrate, i was able to reproduce it with an air compressor, blow the air close to the rubber and low by the hood to replicate air blowing while driving, hope this helps.

 

Yeah... thats the source of another strange noise as well. If you go through a car wash water will get under there and when you drive you can hear it "burble" until it dries out!

 

I just recently purchased a used 2006 Ford Escape Limited with a V6 (17,000 mi) and I have the same exact whine problem that you describe. It starts around 55 and gets louder until its loudest point at about 65 and then almost disappears around 70 mph. It is directly linked to when I'm on the accelerator...as soon as I let off, it stops...and starts back up as soon as I press on the accelerator again. Due to this, I ruled out wind and tire noise as the problem. I've told the dealer about it but haven't brought it in yet. It sounds almost like your driving over a concrete deck bridge, but not as loud...although the frequency is just right that you can hear it through the radio. It's gets rather anoying because I do most of my driving on the highway at 65 mph. It doesn't seem to affect the performance, but I would sure like to correct it!

 

SDF-
That explains mine exactly. I also noticed that at lower speeds there's a lower pitched whine. Whenever I apply the brakes (no matter how light or firm) and press the accelerator, it starts up. I know it's nothing to do with the electric engine--that is still silent. I'm bringing my car in next week.

 

Queenfan,
Were they able to determine the cause of the noise? Mine is scheduled to go in on Wednesday...Thanks!

 

SDF-
Nope. They gave up. Yay for the Ford dealership!
I know for a fact now that it's not wind--it did it with the windows open over the weekend. Good luck, and if you find out anything please let me know.

 

...will do...

 

QueenFan,
Sorry I never got back to you on this...I thought I did. I was just checking in to see if there was any new discussion and found out that I never got back to you. Anyways, the Ford garage put new front half axles in mine hoping to solve the problem, but it didn't make a difference. It is still doing it and no one seems to know why.

 

My 2008 MMH is doing the same thing from 60-65 and 25-30. Looks like no one has sorted this out yet...I don't have much confidence in the dealer, but will start there.