Advance Adapter’s RubiCrawler



Some day I plan on having a dream Jeep, that specific model is an 2006 LJ Rubicon with 2″ of lift and 37″ MTR tires and one of the parts that it would include is the new advance adapter Rubicrawler.

The Rubicrawler is a gear reduction box that allows you to have more selections in your gearing choice. Your standard Jeep only has 1:1 gear ratio in 4HI and when shifted into 4LO your generally have some where around 2.72 unless that Jeep of yours is Rubicon and in that case it would be 4.0:1. This means that your drive shaft will rotate once time every time the engine does one rotation in 4HI. Where as in 4LO the drive shaft will only rate once every time the engine does 2.72 rotations.

This where the Rubicrawler comes in handy because it give you additional choices for gearing. The options are 1:1, two choices of 2.72:1, and 7.40:1 for wranglers produced before 2006, and for you lucky ones with the Rubicons package the options are 1:1, 2.72:1, 4.0:1 and an impressive 10.88:1. Now some of you maybe saying that the 4.0:1 gearing is good enough, I would disagree because I think this allows you to run much better highway gears and still have a very low gear ratio. Instead of gearing my dream Jeep with 5.13 in the differentials, I will choose 4.88 and maintain reasonable gas mileage and still have a lower gear ratio than factory Jeeps.

The factory transfer-case shifter is replaced with a twin stick design in the same location that requires no modifications to the interior. The best part of the Rubicrawler is that it replaces section of the drivetrain that nothing more than open space. Meaning that you do not have to modify the drive shafts in anyway, or anything on the Wrangler for that matter.

There is one drawback to the Rubicrawler, which is also the reason why it is low on my dream build list, the price. The Rubicrawler costs $1784.75 and that isn’t installed, but hopefully with time demand will increase and reduce the price of the Rubicrawler. Be sure to check out the other things Advance Adapters sell because this isn’t their first great product they have produced.


  1. […] Jeep Wrangler 2006 LJ Rubicon, which is the Advance Adapter Rubicrawler and you can read that post here. To get on track with the next item in a list of items for my dream Jeep that I plan to update more […]

    1. Ralph Jones Avatar

      Did you ever get your LJ? I have a 2006 LJ and I can say with 100% certainty, that 4.88 and 5.13 would absolutely suck with 37″ tires and a 4.0. I had 4.88 with 33’s and it was just OK. When I went to 35’s, 4.88 was horrible and left the trans constantly searching for the right gear. I bought and installed a Currie D44 for the front and went 5.38. While this seems super low for 35’s, the drivability is great. As far as saving gas because of lower RPM’s, No. Rpm has very little to do with mileage. 4.88 and 37″ tires will lug the motor and you will have to keep your foot in it all the time… You WILL hate it.
      4.88 and 37’s with a V8 swap, and you’ll be fine.
      I hope this message finds you well.

      1. Schwarttzy Avatar

        I did not ever get that LJ I wanted. But I’m very happy with my H3 Hummer with both the Off-Road and Luxury Package along with a factory 5.3 GM V8 Engine. I had 4.10 gears in my ZJ Jeep Grand Cherokee and 33’s and was just fine.

        1. 5.38s is the only way to go with 35s and the 42RLE for the road bc it keeps you in the proper RPM range. I don’t need OD until 75mph. Gas mileage is t better when you are lugging along with 4.88s which is exactly what will happen. It’s well known info if you go into the forums and talk with the guys who know their stuff.

          1. Schwarttzy Avatar

            Thanks for your point of view. I still stand with my original statement from January 7, 2010. A long time ago I had ZJ Cherokee with 4.10 gears, on 33’s, and a I6 that worked great, scaling out to 37’s with 4.88 gears seem to suit me fine. Years have passed and I’m quite happy with my factory 4.10 gears, 35-inch tires, and the GM 5.3 LH8 V8 in my H3 Hummer.

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