Light snow (few inches) on a hard-packed gravel road. An empty Suburban is stuck with excessive force in a pothole on perfectly level ground - the front driver's wheel in a ditch, which lifts the rear passenger and I tremble. Attached the chains to the rear axle, put the truck on 4- here (the front axle doesn't engage, so I just give my rear axle a low range) and gave it some fuel. I immediately felt the tracks dig into the ground and after 5 seconds, with no excessive throttle and wheel spin…