Soooo.. I just lifted my 2012 JKU rubicon, and slapped on some second-hand 37s. I have the stock 4.10 gears in the D-44s, with a 6-speed.

That being said, I'm at a bit of a crossroads here. My original plan was to run 5.13 gears and slap on some 38s and be done with it. However, recently I have been hearing some differing opinions. I know that 5.13 gears with a manual trans and 38s would wind up giving me slightly lower gearing than stock. That is what I want (I think) because I don't feel like the gearing was low enough to make 4-Hi useful, plus I plan on pulling a small uhaul trailer behind this thing when I move soon. ....moving roughly 3000 miles away, by the way. (going to cost a small fortune in gas to get there)

Am I wrong with thinkint that 5.13s would be the best choice?

For those of you who have already regeared your rigs, are there any of you who have 5.13s in a '12 with a 6-speed? If so, would you do it the same way if you had the chance? I am not made of money, so I only can afford to do this once.

Thanks for your thoughts on this! I'm completely torn on what to do.

 

I have a 13 auto with 4.10 and had a 12 auto with 4.10, both on 37. I also had a 13 3.73 with manual on 35. To me, 5.13 is overkill. I would think 4.56 is what you want, 4.88 tops. I know you are making a trip but that's a one time thing. 5.13 is what you would have geared on the 3.8. Also keep in mind that as you go lower in gear, the R&P gets smaller and weaker. With that kind of meat, you raise the chances of a gear failure. $$$ to fix. Just my thoughts.

 

Matt are you 100% happy with running factory 4.10's and 37's with an auto. Getting ready to place a huge order with Northridge and from everything I've read I can get away with the 4.10's. last jeep was a 2010 and I was on 37's but needed 5.13's to be back in a reasonable power band. Would you go to a 4.56 or 4.88 with your 2013 or does the 4.10's get the job done with no complaints whatsoever.

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Could it use a quicker start? Sure. However, is it worth $1500 and 1-2 mpg less? No. If I had a free regear, I may do 4.56 but I think the higher rpms on the interstate would bug me more than the slow start. With the 4.10 I am happy. Once you are in second gear, it feels like a stock jeep to me.

 

Cool, thanks bro. I love quick starts but I guess I'll just have to see if its too bad.

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Just re geared to 4.10s from 3.21s in my 2012 auto Sahara. I run 35" KM2s.

Love it. Holds 5th up moderate inclines at hwy speeds and had a stiff headwind at 75-80 coming back from Jeep beach with no downshifting or gear hunting.

For 37s or 38s I think 4.56 would be perfect, but not worth the $$$ for such a small difference from your current 4.10s.

 

I have a '12 auto with 37's and 5.13's,, and I went too low. At highway speed I'm turning too much rpm,,,,(but its tolerable). Iv heard with the 6 speed, 5.13's are a better match. Having that in mind I would tell you to re-gear to the 5.13's for your towing needs. If that scares you,, go 4.88's at minimum! I disagree with anyone who tells people to keep stock gears with 37's!!! A re-gear will make both your engine and tranny/clutch last longer. Good luck with your decision, and let us know how it turns out.

 

You didn't go to low, you were just planning ahead for larger meats!

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i think i love you!!!,,,, And yes,,,,, my 300th post is a declaration of love for another man! I'm not ashamed

 

Rofl!! That's fucking awesome!

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