The RubiCrawler replaces the 42RLE transmission tailhousing with a 6 pinion planetary assembly featuring a 2.72:1 low range. The RubiCrawler is an exact bolt-in replacement of the tailhousing, so installation is easy and driveshaft lengths aren't changed.
With the RubiCrawler installed, the Rubicon JK or TJ owner with the OE RockTrac 4:1 T-case will now be able to choose between 1:1, 2.72:1, 4:1, and 10.88:1 ratios. The JK and TJ owner with the OE 231 case will have 1:1, 2.72:1, and 7.4:1 ratios. This means that you'll always have the correct ratio, whether crawling or hauling. When installed between the 42RLE and a 4-speed Atlas T-case, the possibilities are mind boggling.
The RubiCrawler will be available after the first of the year. Check out www.advanceadapters.com or www.atlas-tc.com/rubicrawler for more information and to sign up for updates.