I have an automatic 2011 jk unlimited that I am looking to possibly gear. I put 33" tires on her jeep and am looking to lift 2.5" - 4" and run 35's. Has anyone put gears on their jk unlimited automatic and noticed a difference? I am looking for gear responses from people with 33's and 35's. Please let me know if you believe this is a reasonable buy, good power increase, gas mileage, etc.. Mostly a weekend toy, 80% mall crawler, but when I go from my 6.2L truck to her jeep its kind of depressing... We would like to start going on more trails too, so this is also for that......And I just sold my gsxr and the money is burning a hole in my pocket....

Also, if anyone has this set up and lives in northeast louisiana and wouldnt mind showing me how it drives, hit me up!

And yes, I have searched the threads for the past 45 mins., didnt find exactly what I was looking for...

 

I regeared my 08 when I put 315/70/17's on it. I can't imagine what a dog it would have been without them. I put in 5.13's and I'm happy with them. Well worth the money spent.

 

Start with the rpm chart in the Drivetrain FAQ's, stickied right at the top of this modified area. What you will find is that, with an auto, you really can't over-gear. (Find a ratio/tire height/rpm for an auto, then see what size tire a 6spd would need to run to get a comparable rpm. Should be about 5" taller...) The ratio you choose just depends on location and needs.

I went from 3.73 to 5.13, and am now running 5.38's with 35's (33.5" actual mounted height). Gonna suck again if/when I move up to 37's.

Read post #33 here for some great info:
https://www.jk-forum.com/forums/show...=1#post2147185

 

If you don't have a Rubi, then 5:13 is your best option for an auto X or sahara. I have KM2 35's with 5:38's, CAI and 87\tow tune, I wish I had a V8

 

So I have two people pleased with the gears and one in between. How much mpg gain did you guys get?

 

I just installed 4.88's w/35's. Driving to Big D with 3.73's @ 70 mph on stock tires my automatic was dropping down to 3rd gear on the longer I-20 hills @ 1900 rpm's. On the way back home, as Madia would say; "OH HELL to the yeah!" Now it cruises 400 rpm's higher at 70mph with the 4.88's and only dropped down to 3rd once!
It works great for me and around town is really nice compared to stock!

Have a great day!
Gary

 

5.38's on 35's(auto), love them! they are killer in 4L0 with the rubi TC

I get about 16 MPG

 

I went 5.38 rather than 5.13 just in case I wanted to jump to 37's in the future. Do you think 5.38 will be sucky with 37's?

 

Totally. But did you notice my location? 6000+ with constant elevation changes is probably a little different than your typical drive. My performance isn't horrible, but as enlocal mentioned above with his v-8 comment, I would be much happier with more power.

 

Didn't notice your location, that makes since with all your elevation changes!