I don’t have a Rubicrawler but I agree 100% with the biggest benefit is having the ability to run in either 2.72 or 4:1 low range.Some who don't own or have ever used a Rubi-Crawler like to preach that there is no benefit. You won't hear that from those of us who have installed one.
The benefits of a Rubi-Crawler are not limited to low crawl speed as Mr. Bransford seems to suggest. To the contrary, the greatest benefits of the Rubi-Crawler are in the 2.72 underdrive ratio with the transfer case in high range.
Some benefits of the Rubi-Crawler for those who own Rubicons with the NV241OR 4:1 transfer case:
Three low ranges - 2.72:1 underdrive, 4.0:1 from the transfer case, and 10.88:1 by combining the two.
[Caveat: The ultra low range may be a benefit in some highly technical stuff, but so far my 4.0:1 low range has been enough. My evaluation is based almost entirely on the benefit of having the 2.72 underdrive ratio with the NV241OR transfer case in high range. Having the 10.88 compound low ratio is just an added bonus to me, not the primary reason for the modification.]
In my opinion, the 2.72:1 underdrive ratio is an all around better ratio for the easier and moderate stuff in between the technical rock gardens where the 4.0:1 transfer case ratio shines. No more driving along forest service roads, desert washes, etc. in 4 low at very high rpms or shifting into high range and lugging the engine. The 2.72 ratio is the Goldilocks "just right" ratio most of the time for most conditions.
When the Rubi-Crawler is shifted into the 2.72 underdrive the transfer case can be shifted in and out of 4WD on the fly, something that cannot be done with the transfer case in low range. You have both 2.72:1 2WD and 2.72:1 4WD instantly available without stopping and shifting the transmission out of gear.
With the electronic interface provided by Advance Adapters, you can use your factory rear locker in 2.72:1 2WD in addition to both front and rear factory lockers in 2.72 4WD, 4.0 4WD, and 10.88 4WD. All factory switches and indicator lights work as intended in all situations.
Since installing my Rubi-Crawler I have found that I use 2.72 2WD a lot, both locked and unlocked. Generally speaking, I also find that I use the 2.72 underdrive and shift between 2WD and 4WD more than I shift out of underdrive and use my 4.0 transfer case low range instead. It may be not "much more," or "significantly more," but enough more that my Rubi-Crawler has been worth every dime to me.
But as always, YMMV.
View attachment 119411
Then that shall be my next exercise. Thus far I've been satisfied with what the 42RLE can do with 4:1 low range and 5.38 axle gears with judicious use of Black Magic brakes so I haven't experimented much with the 10.88 low range on steep downhills.. . . Shifting the Rubicrawler into low and the t-case into 4low it is so much more comfortable truly crawling down steep grades. . . .
Since ABQWrangler’s profile says he has an 06 SE I’ll assume he has a 231 case behind the 4 cyl engine. He would benefit from double low much more than you will due to the 231’s 2.72 low and assumably lower compression braking from the cyl vs your 4.1 low and 4.0 compression.Then that shall be my next exercise. Thus far I've been satisfied with what the 42RLE can do with 4:1 low range and 5.38 axle gears with judicious use of Black Magic brakes so I haven't experimented much with the 10.88 low range on steep downhills.