So I wanted to give it a few days to be sure, but since I've had the two turbos replaced I have not been hearing the "transmission whine" that had been present for the last couple years:
https://www.fordraptorforum.com/threads/noticing-a-slight-transmission-whine-now.85907/
I think the first turbo failure happened a long time ago and the other one had been working extra duty until it failed too. Looking back the truck has been down on power, but it also coincides with the period of time which I had to switch to regular unleaded fuel; so I've attributed the power loss to using lower octane. Also, thinking back around then, there was an instance where I was under full throttle and fully loaded down with cargo trying to merge back onto a busy highway when the truck suddenly lost power momentarily. At the time I attributed it to bouncing off the rev limiter (paddle shifting manually) but it surprised me because I didn't think I went that high. Hmmm wondering if that was the moment the first turbo went. Sad because I would have been under warranty back then. That was around 55k and its at 92k now. If it really played out like that...BIG IF...then I'd be impressed with the little engine going 37k miles on only one turbo...pulling trailers, hauling firewood etc. On the flip side though its a shame to lose a turbo within the first 55 thousand miles. Who knows if it went down like that I'm just putting clues together.
As far as noises, leading up to the most recent turbo failure I hadn't noticed anything in particular but the engine bay was a little busy sounding...kinda like what you'd expect of a high mileage vehicle. LOL...in my own defense I do have a
little trouble hearing. But it really hit me how quiet my truck is since I've got it back from the shop.
Here's pics of the impeller: