Kern and 1 Wild. If you read the article posted in the op’s link it shows the math. The rubicon has a steep ratio for 4 low and the math came out to a few hundred less than 55k rpm. It sounds like they were flat towing behind a motor home. Probably didn’t even know anything happened until they tried to start it.
I'm fully capable of doing my own math... Just need the right numbers.... When I searched the web the ratios I found for a Rubicon don't agree with the articles numbers.... No biggie... Both take the engine RPM's well past redline...
What honestly surprises me is the fact the engine even turned over... With relay steep gear ratios usually the output can not drive the input against the gear ratio never mind against the compression of the engine.... With that high of a ratio I'd expect it to simply drag the tires....
My guess is it wasn't really in the absolute lowest gear but actually a gear that would only spin the engine say 15,000 RPM's...