Possible Transfer Case Issue
 

Hey, first post, I recently took my 4WD Blazer to a shop rfor an e-test, one of the test's requires the car to be run on a dyno, my car is exempt from this test as your not supposed to run it on a 2 wheel drive dyno, I think the shop may have run it on the dyno anyway, now I'm worried that damage has been done to the transfer case, but I was told there is no way to check, does anyone know how the drivetrain system works, like details as to why all 4 wheels need to be spinning at once? thank you

As long as the transfer case was in 2WD and it was the back wheels on the dyno it should be fine