The 4T45e transmission is not built in mexico. The fact that your HHR was built in Mexico had nothing to do with your transmission problem. BTW the 4T45e is a durable transmission minus the occassional valve body or solenoid issue.
And the post about a 2012 Honda Accord with rust issues. If you would read that thread it is an isolated incident. There is likely a history about the car which caused the rusting and the owner is taking it to the dealer because it was a newly acquired veh to him and is looking for manufacturer assistance. Please read the thread again before coming to conclusions.
In my experience cars are built better now than they were decades and decades ago. Cars from the past would wear out. Suspensions parts, engines, transmissions, interiors, window cranks, door hinges, anything mechanical. Todays cars are much different. They dont wear out like their predecessors, you are much more likely to experience something to break, not wear out in a newer built car. Im around old cars all the time. Sure, everything still works on the cars but everything is worn out. The steering, the door lock plungers, the turn signal level, gear shifter, windshield wiper linkages all wear out on old cars and are usually never replaced. Thats why an old car from decades ago feels worn out and the term "clunker" comes. But many people say that they were built better back then because they havent "broke" yet... Those parts on newer cars are more likely to break which requires immediate attention, and in general the car doesnt feel worn out. Engineering has come a long way.
The 2006-2013 Impala has a design problem that GM needs to take care of. I am upset about Buick importing cars from China but hopefully its not a trend.