Just wondering what Selec-Terrain setting (other then Auto) is suitable for driving long distances on loose gravel roads???
I'd suggest leaving it in auto, and don't use sport mode if you have the Hemi and an unsteady foot.
The definition of long distance may vary depending on what is meant by long distance.
If they are really loose, try "snow"
The selector modifies power distribution as well as height in some modes.
For example, in snow mode, it puts your jeep in normal ride height if in high range, or lifts it a bit in low range.
A hard copy of the Owners Manual is available if you are the initial buyer. Just input your VIN at Jeep SUVs & Crossovers | Official Jeep Site | Jeep
for owners section.