So, with an AX-5 and 5.38's a 4:1 would look like this; 84/50/31/21 which is closer to 2.72

Here's the gear spread for a NV4500 with 5.13's which is what I'm planning on running. I've spaced the ratios out so they kinda line up respectively. This includes 1:1 in the transfer case which are generally the 3 lowest (numarically) numbers then the 5th. The Rubicon's 4:1 in 4th is the same as 1st in 1:1 so I omitted one.

I threw in your ratios into the chart. Interesting thing is 3 & 4 in 6.74:1 are actually marginally higher (numarically lower) then 2.72:1 in 1 & 2. For all intensive purposes though they are the same.

01.00:1 -------------------------------------------------------------------- / 28 / __ /15 / __ / 8.6 / 5.13

Rubicon NV3550 4:1--------------------------------------- / 66 / __ /38 / __ / 22 /16 / 9.5 / 5.6 / 4.10

02.72:1 ----------------------------------------------- / 78 / __ / 42 / __ / 28 / 23 / 15 / 13 / 8.6 / 5.13

03:00:1 ---------------------------------------------- / 86 / __ / 47 / __ / 28 / 25 / 15 / 15 / 8.6 / 5.13

04.00:1 ----------------------------------------- 115 / __ / 62 / __ / 34 / 28 / 20 / 15 / __ / 8.6 / 5.13

04.30:1 -------------------------------- / 124 / ___ / __ / 67 / __ / 36 / 28 / 22 / 15 / __ / 8.6 / 5.13

Scott's AX-5 6.7:1 -------------- / 141 / ___ / ___ / 84 / 57 / 52 / 36 / 34 / 21 / 14 / 12 / 7.5 /5.38

05.00:1 --------------------------/ 144 / ___ / ___ / 78 / __ / 44 / __ / 28 / 26 / 15 / __ / 8.6 / 5.13

11.70:1 ------------- /337/ 182 / ___ / ___ / 100 / 78 / 60 / 42 / __ / 28 / 23 / 15 / 13 / 8.6 / 5.13

What I've noticed is that when you switch down from say, 11.70 3rd & 4th gears basically overlap 4.3 in 1st & 2nd with the 1st and 2nd numerically lower. And it continues with 2.72 and 1:1.

4.3:1 would match with a stock Rubicon though it's not account for the additional 95 lbs-ft of torque. Which the 5:1 would probably make up for. Also, it looks like the 11.70:1 isn't that good matchup and that the 10.34 might be better. But that's 3.8:1 and the ratios between 2.72 and 3.8 are going to get a lot closer.

Actually let's do this a different way. Lets think of gears as torque multipliers instead. 235lbs-ft for the 4.0L. Using a TJ Rubicon as an example that's 15.454.54 lbs-ft. Now if you swap that 4.0L for a 2.5L without changing anything else that's 9864.6. Here's some additional combos. This of course is assuming the tires are the same across the board.

AX-5 x 3.92 x 4.11 = 2416.7

AX-15 x 3.83 x 3.75 = 3375.2

NV3550 x 4.01 x 4.1 = 38636

AX-5 x 2.72 x 4.11 = 6573.4

AX-5 x 2.72 x 4.56 = 7293.1

AX-5 x 5 x 4.56 = 13406.4

AX-5 x 5 x 5.13 = 15082.2

NV3550 x 4 x 4.1 = 15454.5

NV4500 x 4.3 x 5.13 = 18562.6

AX-5 x 6.7 x 5.38 = 21195.1

NV4500 x 5 x 5.13 = 21584.5

On another note, I've been playing around with this site.

https://www.blocklayer.com/rpm-gear.aspx Great for comparing R&P and Tire sizes, too. This should show stock AX-5, NV3550 and NV4500 already entered into it.

https://apx6u.app.goo.gl/CJptLooks like 5.13's should be the perfect choice for 33's when accounting for an additional weight. 5.38's for 35's is within 1 mph too. Anyway... You can also add in the transfer case ratio.