Years ago I went to the Arlington TX GM plant, before making Tahoes they made the Chevy Impala RWD and Buick Roadmaster wagon. As soon as the vehicle came off the assembly line it went to a "dyno" booth. The vehicle was VIOLENTLY ran through the gears, trust me after 500 miles you can thrash the shit out of them.
That was part of the test at the mitsubishi plant. (rivian now) Everything came down to the end of the line and was run up, some to 100mph depending on who was driving, emissions checked then aligned and etac (tranny in chryslers was programmed) was done. Then we would take them out to our track and first part of test was wide open acceleration to make sure it shifted at the red line. Then we double checked the functional items and shook the shit out of it to check for loose objects which you would be surprised what the line people would put in stuff.
