Hey all,

what's needed to change a JK rubicon's rock trac transfer case from a 4:1 ratio to a 2.72? Is it possible to do so by changing gears? Or would the entire transfer case need to be swapped for a X/sport/sahara t-case?

In case anyone's wondering WHY, the reason is there are no rock-crawling opportunities within hundreds of kilometers and only sand, sand and more sand, and the rubi t-case is only useful for maneuvering in such an environment when set to 4LO.

 

Yeah you need to swap the case out. Wish you live here, I would gladly swap with you, as I want a rubi t-case :P

And I know what you say about the sand and such. The 4:1 low is WAY to low for that terrain.

 

I imagine there are lots of people who would be willing to trade t-cases with you.
Put that word out. That would be the cheapest way to go.

Or, you could install a RubiCrawler if you have an automatic, and have the ratios of BOTH t-cases.

 

I have heard of some kits that put 2.72 gears into some empty space in the Rubi xfer case, allowing you to have 2 different low ranges. Someone already said that though haha

 

It goes between the automatic transmission and the transfer case.
RubiCrawler is its name.

 

The RubiCrawler

Heres the info

edit/ add:

This units fits Jeeps 2003 to 2009 with the 42RLE automatic overdrive
This new reduction unit replaces the stock 42RLE tailhousing with a 6 gear planetary reduction box featuring a 2.72 low range. This is a true bolt-in doubler that couples to the stock Jeep transfer case or an existing Atlas transfer case.

Features: The RubiCrawler increases our available gear ratios allowing you to gear your Jeep to the terrain in which you’re wheeling on. The various ratios will allow you more control of the vehicle which results in extreme off road performance while maintaining a fun and safe offroading experience.

Ratio Possibilities:

Stock Transfer Case Functions:

With the Rubicrawler installed in any Jeep, The Normal two wheel drive feature of your Jeep does not change. The city or rural road handling of your Jeep is the same as it was the day you bought the Jeep.

Stock Transfer Case Functions with the RubiCrawler in High Gear:

Rubicrawler in high range and the transfer case in four wheel drive high range (all Jeeps). The gear ratio of the transmission does not change. This feature gives you power to all four wheels.
Rubicrawler in high range and the transfer case in four wheel drive low range (non Rubicon Jeeps). The final gear ratio with the transmission in any gear is reduced 2.72 times lower. This feature gives you power to all four wheels.
2a. Rubicrawler in high range and the transfer case in four wheel drive low range (Rubicon Jeeps). The final gear ratio with the transmission in any gear is reduced 4.0:1 times lower. This feature gives you power to all four wheels.

Stock Transfer Case Functions with the RubiCrawler in Low Gear:

Rubicrawler in low range and the transfer case in two wheel drive (all Jeeps). The final gear ratio with the transmission in any gear is reduced 2.72 times lower. This feature does not give you power to all four wheels, but provides slower speeds and more throttle response for easy trail use. The nice feature of this is that you have more torque and better handling.
Rubicrawler in low range and the transfer case in four wheel drive high range (all Jeeps). The final gear ratio with the transmission in any gear is reduced 2.72 times lower. This feature give you power to all four wheels and provides a shift on the fly option for four wheel drive. The New Process transfer case can be shifted into high ratio on the fly; so if you’re in sand, mud or offroad trail and need power to all four wheels this is a great option.
Rubicrawler in low range and the transfer case in four wheel drive low range (non Rubicon Jeeps). The final gear ratio with the transmission in any gear is reduced 7.40 times lower. This feature gives you power to all four wheels. This is an extreme crawl ratio that provides a slow controlled approach to an obstacle.
3a. Rubicrawler in low range and the transfer case in four wheel drive low range (Rubicon Jeeps). The final gear ratio with the transmission in any gear is reduced 10.88 times lower. This feature gives you power to all four wheels. This is an extreme crawl ratio that provides a slow controlled approach to an obstacle.

Ratio possibilities with a -
Stock New Process 231/241 are a 2.72:1 and a 7.40:1
Stock NP Rocktrac are a 2.72:1, 4.0:1 and a 10.88:1
Atlas 2.0 are 2.0:1, 2.72:1 and a 5.44:1
Atlas 3.0 are 2.72:1, 3.0:1 and a 8.16:1
Atlas 3.8 are 2.72:1, 3.8:1 and a 10.44:1
Atlas 4.3 are 2.72:1, 4.3:1 and a 11.70:1
Atlas 5.0 are 2.72:1, 5.0:1 and a 13.60:1




The RubiCrawler’s shifting mechanism utilizes push/pull cable technology for a smooth and easy shift. The universal cable shifter is included with the purchase of your RubiCrawler. (The universal shifter should be used if your vehicle is equipped with an Atlas transfer case)

We also offer a twin stick cable shifter for the Jeeps. These kits are designed to fit the stock TJ and JK consoles.

The Jeep TJ's twin stick shifter replaces the standard hard linkage. We have designed a twin stick shifter that comes through the stock console for a clean installation that operates the RubiCrawler and the stock NP231 or NP241 transfer case.

The twin stick JK shifter also provides a twin stick shifter through the stock console. This kit retains the stock transfer case cable with the addition of the new RubiCrawler cable.

These shifters are an additional charge but are the best suited for most installations. (Note, if your vehicle does not have a stock transfer case, the universal shifter should be used.)

 

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Rubicon case is on the right. You can not just swap the gears/internals out.

 

I have a manual, so the rubi-crawler is not an option for me.

And here in CA, everybody wants the lower low range.

 

I have an auto x transfer case, will that work in your jeep?

 

I had read about the rubicrawler before... when I first saw it I got excited, till I noticed it was for autos only :( My rubi is manual.

Teraflex: thanks for the tip.

2k2wranglerx: Nope, it must've been someone else.

aussieguy: nope, it's manual. AFAIK it has to be a manual t-case... right?