I love granny gear -- I've heard it called "house moving gear" -- but I've only found it on 2WD trucks, meaning that low range is required to get essentially the same effect on a 4WD vehicle.
I had an International Travelall back in the 80's. It had a 345 V8, a granny low 4-speed and 4wd. You could put it in granny low, and 4wd low range, let the clutch out at an idle, hook it up to a trailer and walk beside the trailer loading form boards for curbs and gutters for over a mile. Just had to put a bungie cord on the steering wheel to hold it straight. Did that at 3 separate shopping centers we built when I was doing concrete. Like a lot of those rock crawlers I watch on YouTube, that thing would run out of traction before it ran out of power.