For those with 2012 and 4.10/4.56
 

So who's running a 2012/13 with 35's and 4.56's or 4.10's? Wondering how you like it and how it does on the highway, rpms @ 70, mpg? I've seen the new ratio charts and what not so no need for those, just looking for some first hand experiences. Any of y'all with 4.10s have any intention of regearing with 35's?

I currently have 3.21's (manual) and while its not that bad, I am looking to regear to either 4.10 or 4.56. I do a LOT of highway miles (27,500 total miles in 13 months) @ 70+ so that is the only reason i'm kind of weary about 4.56's with the new engine. I do a lot of wheeling too, every or every other weekend, so obviously that part of me wants 4.56. Will the crawl speed between 4.10 and 4.56 be that noticeable?

Thanks for anyones help.

If your JK is heavy, get the 4.56 gears. They will also be better if you decide to run 37" tires in the future.

My 2012 JKU Rubicon auto ran 4.10 gears with 35" tires for about a year with no problems. As my JK got heavier with bumpers, winch, skids, sports cage, etc..., the 4.10 gears still worked ok with 35" tires.

I changed my gears to 4.56 because I wanted 37" tires. I was running the 4.56 gears with the 35" tires for about a month while I waited for my 37" tires and wheels. I had better acceleration and didn't notice any negatives on the highway except for a slight reduction in gas mileage. I don't know if the reduced gas mileage was because of the gear change or because I went to larger/heavier axles or both, but it wasn't terrible.

My gas mileage now is between 14 and 15 mpg with a 50/50 mix of city/highway, but my JK is heavy and my 37" tires and wheels weigh about 125 lbs each which doesn't help with mileage.

13 JKU here with 33", heavy front/rear bumpers and a winch. I have about 400 miles on my 4.56s. I also have the 6 speed. Do the 4.56s. You will love them with the bigger tires.

I'm turning about 2600 RPM at 70 with lots of acceleration through all gears. Besides getting 6 gear back on the highway, I can actually cruise with it and pass on hills without downshifting.

I don't know, that just seems like a lot of gear for me. I know my RPMs would be lower with the 35's but still :dontknow2:. I have a 35 minute drive to work cruising 70-80 the whole way. Don't want to be runnin 2800 rpms for a half hour lol. I don't mind having to downshift to 5th on hills. 6th gear doesn't have to pull 70 up hills, its an OD gear meant for cruising.

Too bad i couldn't afford a Rubicon in my situation. I think 4.10's on the highway and the crawl with the 4:1 transfercase offroad would be perfect with 35's :sad2:

If 35" tires is the largest you want to run the 4.10s will be fine. There are thousands of Rubis doing it now.

'12, 35" AT tires, 4.1

The 'ECO' display doesn't light up much, that's all.
No lack of power on or off road, no reason for re-gearing.

yeah I know 4.10's would be fine, but is it worth $1500ish to go to 4.10's instead of 4.56 is what i'm trying to answer lol... one of those impossible answers that you don't know till you try i guess :doh:

Definately not regearing. Running 34"s ( true measure) and at 70 I'm revving approx 2300 with 4.10s and the automatic

I've been running 35's with 4:10's for 27k miles (in 9 months). I'm a fully loaded down JKU, and have no complaints about acceleration or cruising at highway speeds. My MPG's suck, and I can't imagine how much worse it would be with 4:56.
Moab raffle blessed me with a set of 37's in the garage, and I'm still not inclined to regear further.

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.