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For those with 2012 and 4.10/4.56

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Old 04-12-2013, 06:37 AM
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Originally Posted by Kbryant88
If your going to spend that much money why not go with 4.88 I went with them and there great.

My commute to work is 30 min on the high way and I'm doing about 2300-2500 rpm the Eco light is always on, and I'm getting 17.5-18mpg hand calculated.

The 4.88 goes up inclines like nothing plus it'll give me room to grow to bigger tires in the future.
hmmm. 2300-2500 at what speed? Yours a 2012/13?
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Old 04-12-2013, 06:42 AM
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Originally Posted by kh202
hmmm. 2300-2500 at what speed? Yours a 2012/13?
kh202....4.88 is the worst advice ever.

I have a 2012 Auto Unlimited with front bumper, winch, and 35" KM2s. I put my deposit down and am regearing next week to 4.10s. Its the perfect gear for 35s and mixed wheeling and hwy. They cost more as they only come from Dana.

My buddy has the exact setup I'm going to run and he is at 2500 RPM at 70MPH.

4.56s will put you right at 2700 RPM at 70 and about 2900 RPM at 75.
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Old 04-12-2013, 08:21 AM
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Originally Posted by rays0852
4.56s will put you right at 2700 RPM at 70 and about 2900 RPM at 75.
That's about right, I'm running 4.56's in my '12 JKU Auto and that is what I'm seeing. 70 mph= 17.5mpg and 75mph= 16mpg. 4.56's were a good choice for me but to each his own.
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Old 04-12-2013, 08:25 AM
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Originally Posted by kh202

hmmm. 2300-2500 at what speed? Yours a 2012/13?
2012 2 dr automatic going 60
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Old 04-12-2013, 08:27 AM
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Originally Posted by flatattack

That's about right, I'm running 4.56's in my '12 JKU Auto and that is what I'm seeing. 70 mph= 17.5mpg and 75mph= 16mpg. 4.56's were a good choice for me but to each his own.
What size tires do you have.
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Old 04-12-2013, 08:28 AM
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5.38's and 37" Krawlers... would not change it for the world.

Drove 6 hours to Moab and had no issues...
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Old 04-12-2013, 08:32 AM
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Originally Posted by Dynomax
5.38's and 37" Krawlers... would not change it for the world.

Drove 6 hours to Moab and had no issues...
Is that the new 3.6. How was the rpms at 70. Also would the 5.38s be good with 40s too. I was thinking 4.88s for my 37s but wanted 5.13s for when I go to 40s later.
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Old 04-12-2013, 08:32 AM
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Originally Posted by Kbryant88
2012 2 dr automatic going 60
Yeah that's a little too much gear for me. Speed limit is 70 on way to work.
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Old 04-12-2013, 08:35 AM
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Originally Posted by Dynomax
5.38's and 37" Krawlers... would not change it for the world.

Drove 6 hours to Moab and had no issues...
Nice. Haha maybe i'll just slap the 5.38's on and just get a cheap DD
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Old 04-12-2013, 08:48 AM
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Originally Posted by rb1boxer_3
Is that the new 3.6. How was the rpms at 70. Also would the 5.38s be good with 40s too. I was thinking 4.88s for my 37s but wanted 5.13s for when I go to 40s later.
2013, the RPM's at around 70ISH were about (if i remember 2600) The goal is 40's someday hopefully. I originally got the axles with the 3.8 in mind but got a great deal on a 13.

Originally Posted by kh202
Nice. Haha maybe i'll just slap the 5.38's on and just get a cheap DD
Yea, MPG is not the best, I think I am around 14 average right now. I get better in my diesel truck on 35's. Or I just jump in the wife's VW diesel and get REALLY good MPG... but the JK is a lot cooler....
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