It's nothing new...
My 2014 Corolla (Made in Missouri) has a good bit higher Domestic content that that Mustang and the 08 Corolla I hade (Made in Fremont California) was higher yet.
Getrag has many manufacturing plants but none in the USA.
Getrag makes good transmissions, I think if they supply for the American market that they should build them here. Oh sorry, I start dreaming again...
I have had a few cars with Getrag trannies, never had a problem with any of them. (6sps in Vettes)
As others have stated ALL cars today are a product that could be called League of Nations. It varies from where the parts are made to where they are built or assembled. Rest assured there is no 100% made in USA car or truck; in fact the percentage will be much (much) lower.
A lot of this is due to what is so elegantly call Global Economy, NAFTA pops into mind here!![]()
You won' find a car manufacturer who doesn't have some Chinese parts anymore.
You can also go to this site & determine how much of any vehicle is considered US made, all the way back to 2007:
NHTSA Part 583