Here is some info I found on the 6-speed manual transmission used on 2005 and up 3.7 L KJ's along with some crawl ratios I calculated for various rear differential ratios.
Found this on the NSG 370 Close Ratio 6-speed Manual Transmission:
http://www.swiftindavis.com/sblog/index.php?itemid=347
Gear Ratios for the 6-Speed Transmission:
1st-4.46:1
2nd-2.61:1
3rd-1.72:1
4th-1.25:1
5th-1:1
6th-0.84:1
This means with the 2.72:1 NP241J Command-Trac transfer case and a 3.55 differential ratio we have a Crawl Ratio of 43:1 in first gear!
Jeep Liberty 6-Speed Manual Transmission Crawl Ratios
With 3.55 differentials - 43.1:1 crawl ratio
With 3.73 differentials - 45.2:1 crawl ratio
With 4.10 differentials - 49.7:1 crawl ratio
These are quite respectable for a stock vehicle. Note: these ratios do not take tire size into account...a larger tire lessens the effect of a higher crawl ratio.
If you could swap in the Rubicon's NV241 Rock-Trac transfer case you would have a crawl ratio of 63.3:1 !
Rock-Trac is available here and other places.
Rock-Trac 4:1 Transfer Case
Info on the other transmissions can be found here:
Gear Ratio Calculator
John
];')