How to calculate crawl ratio

Ask any old school off-roader and they will say that a "low gear transfer case" is what separates a 4WD from an AWD.  So, that was true less than a decade ago, and times have changed.  One of the largest manufacturers of transmissions  ZF Friedrichshafen started offering their ZF9.  Vehicles like Jeep renegade/compass trailhawks, the Honda Pilot/Ridgeline/Passport, LandRover Discovery sport have the capable ZF9 transmission.  Gearing is a little more aggressive than a Toyota Tacoma in 4LO 2nd gear.