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Discussion Starter · #1 ·
i have a 2012 jk 6 speed manual with 3.21 gearing. i just got my 15x8 mb tko and 35" goodyear mt/r wheels and tires. i will be ordering my 2.5" aev dual sport lift this week. i could really use some advice as to which gearing to go with for what i will be running. most of my driving will be on the roads and highways. i will do some light wheeling. mainly the mountains and logging trails of pennsylvania and a 4wd park that has recently opened. all help will be greatly appreciated!!!
 

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I AM THERE4 I JEEP
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For a manual 3.6 I believe 4.88s are gonna be the best match. Lots of good recommendations on Yukon gears.
 

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Everyone here will tell you 3.73 or 4.1


Im guessing you probably know the cost will be up there(a grand or so). Should have got the factory 3.73 for the extra 75 bucks or w.e it is.

Best of luck man
 

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You should swap in a front D44 so you can run 4.27 gears. That's exactly where you need to be... :whistling:
 

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ESP said:
For a manual 3.6 I believe 4.88s are gonna be the best match. Lots of good recommendations on Yukon gears.
Even with a 6 speed? That's what I've heard for a manual on the 3.8. Do you think 4.56 would suit better? With heavy mtr's it could work with 4.88
 

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derf said:
You should swap in a front D44 so you can run 4.27 gears. That's exactly where you need to be... :whistling:
Might be cheaper to stay stock and go to 4.56
 

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Might be cheaper to stay stock and go to 4.56
If he's looking to save money he could get the D44 front and go with 3.92s. That would give him better highway economy to save money and he wouldn't have to replace his rear carrier. :angel:
 

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Take it from someone with 4.88's you need 4.56's. I know that I have the 3.8 Auto but the RPM's are what matters. And I can tell you what it feels like when you might have too many rpm's at higher speeds.

Saying that:

Since 4.56 gear sets are hard to get in any good quality gear set it comes down to two factors:

Do you need better highway capability? (get 4.10's)

or

Do you need more towing and off roading capability? (get 4.88's)


You will get great low end power out of the 4.88's but you will have a higher RPM at highway speeds which will cost you gas mileage at speeds greater then 60mph. Saying that you can get better gas mileage at lower speeds below 45mph because you are at a better power band at lower speeds. The 4.88's will help turn over the heavier tires too.

4.88 will make it a horse at lower speeds but 4.10's will give you a much better feel at higher speeds. I just took a long trip trip last month and the rpms' were just too high for the trip, not bad but not good either. I actually get the same gas mileage as I do driving around town.
 

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Bah, get the 4.10's with the 6 Speed and the PentaStar 3.6l. What I have and there is plenty of power and still getting decent gas mileage.. no need for 4.56 or lower.
 

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Not sure, I was trying to get them and those that sold them seemed to not have in stock and Yukons and other good gears just don't carry them. Guess they are just not popular enough to stock. Several of the cheaper gear sets carried them but I was advised that I would regret getting them for either noise issues or just poor quality.
 

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i have a 2012 jk 6 speed manual with 3.21 gearing. i just got my 15x8 mb tko and 35" goodyear mt/r wheels and tires. i will be ordering my 2.5" aev dual sport lift this week. i could really use some advice as to which gearing to go with for what i will be running. most of my driving will be on the roads and highways. i will do some light wheeling. mainly the mountains and logging trails of pennsylvania and a 4wd park that has recently opened. all help will be greatly appreciated!!!
Nice! That thing will look like a dune buggy :punk:

My .02 is to install all your toys/lift/etc. and drive it for a while. See how it performs mpg/rpm's/temp/etc with your various forms of driving. Don't go too hard, but take it through it's paces with your stock gears. Keep a record of your stats during various driving conditions and then you can make an informed decision as to what works best for you. Remember to reset your spedo/tach with an AEV ProCal or similar.

Good luck and keep us posted

WAHA
 

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Bah, get the 4.10's with the 6 Speed and the PentaStar 3.6l. What I have and there is plenty of power and still getting decent gas mileage.. no need for 4.56 or lower.
And that why I said it is determined for what you want out of your Jeep. It isn't just bah. It is what do you want from your Jeep, a DD or as I had to take into consideration towing for example. One answer does not always fit every situation. Can you get by with towing or off roading, of course or can you get by at highway speeds, of course but one gear works better for each.
 

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And that why I said it is determined for what you want out of your Jeep. It isn't just bah. It is what do you want from your Jeep, a DD or as I had to take into consideration towing for example. One answer does not always fit every situation.

I'm just speaking first hand.. your 3.8l engine is totally different from his and my 3.6l. The power with the 3.6l with the 4.10 gears is perfect in my opinion for highway, towing or anything else you want to do.. I towed my Rhino to deer camp over the weekend on a 200 mile round trip and average 15mpg on my new 2013 with 30 miles on the ODO running BFG KM2's.. 4.88's would have had the RPMs up around 3K which is way to high.
 

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Discussion Starter · #18 ·
there is little doubt in my mind from reading various threads that i will need to regear. but, do plan on driving the 3.21's for a little while. and i will use the aev pro cal after everything is installed. this is a dd and will see more highways and town driving than it will wheeling. i do take some road trips that involve the interstates so i would like gearing that keeps my rpm's down at highway speeds. i will not be towing anything but would also like gears that will help the low end also. just in search of a good all around gear ratio for my lift, wheel and tire combo. thanks for all the comments and opinions this far and i look forward to reading more.
 

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I have 5.13 on my 3.8L auto with 35's and my rpm at 70mph are 2500. With a manual in my same engine engine 4.88 would be good. So your 2012 manual, or IMO auto too, 4.56 will get the job done for 35's. Possibly even 37's, an automatic 2012 may want 4.88 for 37" tires. Regear is the bees knees.

-Dan
 

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Not me (ELARSON) but on a 3.6/manual:
My 4.88 is running right at 2700 or 2800 at 70 mph yes you are correct.
This is a little high for me- though the poster likes it. I plan to do 4.56s. More and more companies are offering them...I figure by the time I am ready (or that lottery ticket hits)....
Unfortunately I don't think there will ever be a consensus- just IMO. The charts help but each person has preferences....
 
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