I have been having a high-pitch wind noise sound from my ACE 29.2. I've searched everywhere for a solution and tried multiple items, including 4 cans of spray foam in every gap I could find, sealing windows, trying every suggested solution.
Found the problem and solved it.
The front grill is the problem. I removed it and did a test drive and she was super quiet and I almost cried.
Called Thor, they suggested a fix of sealing all the half-exposed square holes around the perimeter where the grill met the fiberglass body. Spent too much time sealing and taping - here are pics of my crappy fix.
Didn't work. And it's ugly too.
So here's how I fixed it - bought a new grill from an online site and replaced it. Nice black metal grill. Looks really nice installed. Here are pics.
If you have struggled with this problem and been driven nuts by the high pitch squeal like me, try this solution. I can probably share the site I bought the new grill material from if someone wants to know.
Hope this helps someone else out there struggling to find a solution.