Its a 5 speed with a granny first. Only real difference from 5 speeds.the 6-Speed NSG370 seems to have pretty different gear ratios!
It allows sightly higher gearing than a 5 speed as you have the option of turning granny gear into more of a street gear by adding larger tires
Your drive ratio is axle x trans gear ratios.lower axle ratio changes will net you a lower crawl ratio and trans gears closer together in rpm at the cost of top speed. Gearing down will not make your jeep pull a pass easier for a given mph. It still takes the same power to get work done.
You should definitely have a different ratio like 4.10 or 4.56 for 33s regardless of where you live. But it won't give you more power.
If you want high altitude power you need increased compression ratio,forced induction or more cubic inches.
Some people mention fuel injection. It has nothing to do with pumping losses at altitude.
I have a 500hp truck. When i go to 5000ft and above guaranteed it is no longer 500hp. It may be passing everything else but it won't spin the tires at 70mph anymore,lol