Preferred gear ratios are 100% opinion.

That being said, if you are spending the money for a regearing, and planning for 35s, I would go 4.56 or 4.88.

I have a 3.6 6speed Rubi on 35s. She is a bit heavy, about 700lbs overweight going by the sheriff's department scales, and I really want to regear. I just haven't been able to justify it as it would be a short jump for me, as I think 5.13s would be overkill.

 

The gear ratio charts found on google are super handy, just search Jeep jk 3.6 gear chart, and check it out (was going to post the image, but it kept coming out blurry). Just remember those are for measured mounted tire size, so your 33s are closer to 32s, and my 35s are closer to 34s.

Happy Jeeping!

 

looks like difference between 4.1 and 4.56 is 2300-2500rpm at 70 with 34's..still thinking 4.1 even though I do live at 6000 ft and most of our trails are much higher around here. Plus I would be adding 200-300lbs to jeep with steel front bumper and winch at about the same time. Tough decision. Still leaning toward 4.1 for better mpg

 

With a manual, you have a little more leeway. To me, 2500 at cruising speed is the sweet spot (**for the 3.6L), but.....lotta people consider 75mph to be the standard cruising speed on highway, so 4.10 might put you right around that with those tires. You know....not an exact science and there are so many variables. Moving from 3.21 gears though, you'd tell a significant difference. That said, I don't think you're gonna see a dramatic change in fuel economy between the 4.10 and 4.56....at least not enough that I'd make a decision based on that. Now, you start getting up there at 3k rpms on the highway and I can assure you the fuel needed starts dropping a bit faster.

 

https://www.jk-forum.com/forums/market/347135

If those have 4.10s in em, you should seriously just consider an axle swap. You'd get the gearing on top of 2 lockers.

 

Guy has dropped his price on those axles that are only 1hr 40 mins from you....down to $2700. Did you ever check those out? They'd be perfect for you and you'd get 2 lockers in the process.