Finally got back around to touching the car to run over a few missed things on my journey to find my weird noise. Checked everything in the driveline one more time. Flushed the PTU which I'm pretty sure was somehow low, flushed the vent hose, drain and filled the RDU and attempted to inspect the rear turbo but that's not happening with my giant hands so planning to run a boroscope down the pipe just to have a look-see.
What I did find was a lot of oil dripping out of the turbo and oil line, and a bolt partially backed out so far up under the manifold I can't reach it without taking down the turbo. Not sure where it goes or what its holding, somewhat mid block. and the pinion seal on the PTU has a small leak.
But the ptu seems surprisingly healthy, the RDU fluid was like new after 20k miles with almost nothing on the magnet, and I dont get any smoke out of the exhaust to suggest a bad turbo. Still going to dig around but at this point I have nothing but a strange noise preventing me from driving it so I'm just gonna run it. Either the issue will reveal itself or it'll just be something she does from now on.
Still going to squirrel away some money for the inevitable parts, GH turbos are only a few hundred more than the Ford PTU, I could've taken my family on vacation but I drive an SHO lol.