WTF happened??
in a way he didn't have a major driveline failure in the way that would screw the sprag. he never broke anything that would over speed the trans. like a broke axle, driveshaft or u-joint. from my experience when the hotrod skids to a stop in 2nd gear it's the low/reverse servor that flipped and locks the trans i reverse and 2nd at the same time. the sprag is fairly easy to test. grab the driveshaft and turn it both ways, if one way is harder it's good. both ways easy it's bad. of course it needs to be disconnected from the rear end.