I wouldn’t walk away - I’d run.....
There has been a lot of problems with the 2018 Expedtions - including numerous safety recalls. Not a good sign.
I may be wrong, but I don't recall there being ANY recalls on the 2018 Expedition/Navigator.
A handful or so of Technical Service Bulletins, yes. TSB is not a recall.
ALL manufacturers have them at some point year in and out, maybe not on every model, and maybe not every single year, (but every year auto manufacturers have them, Ford is a large scale manufacturer, law of averages aren't in it's favor) in truth, but they are not wholly monopolized by FoMoCo.
Keep the required fluid in it, don't worry about it, it's warrantied for what 5years? 6?
I've held the opinion, for a long time, if I don't have any significant problems from any of the vehicles I've bought new, by 2500 miles, I have a good unit. I maintain my own, but I'm also not entirely gentle on any of them either.
2012 Ford Focus Titanium, is the last car I bought a new Ford, and swore I never would again, it was replaced by a Honda within 3 months. Dual clutch crap.
The tranny's basic architecture is from Zf licensed to Ford, though Ford holds patents on their use and intricacies in Ford vehicles as Chevy does with the fwd 9speed also a Zf design. The two of them share the knowledge for the respective units, as Ford will be, if not already using the 9speed in fwd vehicles, as Chevy will eventually use the 10spd in rwd vehicles.
I think possibly some of this whine has to do with the Target/Normal operating temp of the fluid in the 10speed is something like 210°F.
When the tranny is cold (fluid) this could be a bit of a problem for some, that are asking too much from a machine and it's individual components, before they have come up to proper operating temperature.