Crawl ratio (am I doing this correctly?)

Many years ago Teraflex produced a kit to covert the NP231 from 2.72 to 4.0:1, but it is my understanding that they stopped producing the kits due to a weak design and small planetary gears.
In my 98 XJ 4.0L with AX-15 I used the 4:1 for 20 years without a problem (used Redline ATF) which gave me a 70:1 crawl ratio.
 
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So factory Rubicon with NV3550 is: 4.0 * 4.10 * 4.02 = 65.93
Compared to my old YJ AX-15 & np231: 2.72 * 4.88 * 3.83 =50.83
It's definitely noticeable driving in 4lo!
 
So factory Rubicon with NV3550 is: 4.0 * 4.10 * 4.02 = 65.93
Compared to my old YJ AX-15 & np231: 2.72 * 4.88 * 3.83 =50.83
It's definitely noticeable driving in 4lo!
Just think if you had a non-Rubicon it would be 2.72*4.10*4.01 = 44.72 A huge difference and worse than your old 50.83 YJ

I always knew this made a difference but I really found how much this difference makes when I drove my buddies TJ, I was always asking him why is he always on the gas so much well I found it why.

His 1999 TJ with an AX-15 (3.83) Sport Model with a NV231 TC (2.72) and gears (4:88) = 50.84
vs mine
2005 Rubicon NSG370 is (4.46) NV241 Rock-Trac (4.0) gears (4.88) = 87.06 that's over a 50% difference
 
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From what I gather, crawl ratio matters less with an automatic thanks to the torque converter.

The TJ is the only vehicle i've owned that I even considered wanting an auto in.
 
The TJ is the only vehicle i've owned that I even considered wanting an auto in.

If there were other reasonable options than the 42rle, I would gladly make the switch.
 
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So non rubicon's, with the NV3550 had the wide ratio transmissions with 4.1 first gear?
 
Yea as jjvw stated all Wranglers share the same Transmission's, it's the Transfer Case that makes the difference between the Rubicon's vs all other Wrangler models
 
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