i have a 09 jku auto with 3.21 and im wanting to go 35 so i need to regear it. my 4x4 shop wants 1600 for doing it all and they told me to do 4.58 with my jk but on here i keep hearing 4.88 or even 5.13? i live in florida so hills are minimal, where i live on HWY we go 75-80 easy so i need to be able to match those speeds at least but i would rather have kick butt mpg around the 40-60 mph like i do now (i make 17 currently city). thanks all!!

 

I know with 3.21 gears you also need to buy a new carrier to fit bigger gears.

Sent from my iPhone using JK-Forum

 

yea iv heard that too, anyone with those gears with input?

 

With the 3.8 and auto I'd run at least the 4.88s. Running 75-80 won't be a problem at all with them

 

Auto and 35's would be best with either 4.88 or 5.13's. I've heard a few people going with 4.56's but most have manuals I think. I run 5.13's and I am very happy with the setup considering my Toyos weigh more than my Jeep does. I do mostly city and avergae 13 to 14mpg but when I do HWY, I average around 16 to 17. We have a lot of hills here in New England so the 5.13's help a lot. If it was flat, I bet the 4.88's would be a better choice. If you do a lot of hwy driving, I would do the 4.88's and possibly consider the 5.13's only if you ever plan on going to 37's. That's my 2 cents..

 

4.88's with a D30 front axle, 5.13's with D44..

 

I am going to take the plunge and get 5.13s here soon my thought process is like this your Jeep is an investment if you are about to spend $1,600 on 4.56s in a few years are you going to want to she'll out another $1,600 on 5.13s when you aren't happy with the older gears! I plan on keeping my Jeep till I'm dead...and we'll who knows after that!!!

 

Oh gears, another conversation on gears. I current own a 08 JKU auto factory 3.73. With a 315'sx12.50x17 for tires. And have a three in zone suspension lift. I will be doing gears next month. And I still haven't decide what to go with. I'm either going 4.88's or 5.13's. .......

 

mine - 2010 auto, 3.5" lift, 35's,

I would recommend 4.88's even with an auto, you'll get good off-road and on-road performance without sacrificing top end or reaching upper rpms to soon..
5.13'a RP get smaller and that's a breakage risk I didn't want, I also didn't want to lose top end speed for DD and the ability to lock out of OD when needed as I tow a trailer from time to time.

 

4.88s on a 2010 2 dr auto sport with 255/80s in central Indiana with 10% highway driving, 70 mph at 2400,45@1600