I'll keep this short: for any of you who happen across a Ford Edge AWD (in my case, a 2015 with the 3.5) and the customer complains of a high pitched whistle/squeal at highway speed that lasts for 10-20 seconds, check the "seal deflector" on the RH output of the PTO. The deflector is the ring of plastic with vanes on it surrounding the axle shaft. If you can spin the deflector by hand, there's your sound.
At just the right speed and just the right airflow, the loose deflector spins like a pinwheel, causing the whistle noise. The fix is to replace the RH output seal, which comes with a new deflector.
At just the right speed and just the right airflow, the loose deflector spins like a pinwheel, causing the whistle noise. The fix is to replace the RH output seal, which comes with a new deflector.
