You are absolutely right: the crawl ratio is what is important.
The crawl ratio is the number of rotations your engine makes before your tires make one full turn. The ratio is calculated by multiplying your transmission, transfer case, and ring and pinion gear ratios.
Grenadier transmission gearing for first gear: unknown at this point (as far as I know)
Grenadier transfer case low-range gearing: 2.5:1
Grenadier ring & pinion (i.e. axle ratio): unknown at this point (as far as I know)
The actual speed of the vehicle when in low range, in first gear, will also be affected by the tire size. The taller the tire (when holding all other variable constant) the faster the vehicle-speed.
With an 8-speed transmission, first gear could be quite low. We also don't know the ring & pinion, or axle ratio. So we could still have a low crawl ratio even with a not super-low (2.5:1), low range gear ratio.
All the best!
