upnovr

I have a 08 Jk 4 door with 35" tires and 3.73 gears. I have ZERO power and get 8 - 9mpg. Most of my driving is street with an occasional logging road, nothing serious. With this said I am looking to get better gas milage and power on the street. Can someone out there tell me their mpgs with 4.56s and 4.88s and if it helped the power out significantly. $1600.00 for the regear I was not expecting to fork up so I want to be sure on this choice cause the 35s were not one of my better buys. Please no smart ass remarks I know 35s reduce power and mpgs.

scootrrydr

Im not quite sure how you calculated your miles but 9 mpg sounds really low to me. I have the same set up as you and was kinda bummed about getting 12-13 mpg. I kept hearing alot of others claiming 15-18 mpg with a 4 door auto and 35's! I have calculated it out at the pump and also used a GPS unit to be accurate. This isnt my DD and have a economy car to drive so I'm not to worried about mpg but hate the power loss in a head wind! I am also trying to figure out which gears to go with 4.88 or 5.13. So I'll keep an eye on this thread......

rp41

I think if you look you'll find 95% of the people that have changed say 5:13 gears are the way to go. I've read several that went with higher gears and wish they went with the 13's. To me there's no question with an Automatic it's 5:13s. Thats what mine is being changed to next week.

upnovr

are the people you are speaking of getting the 5:13s because they are hard core off road folks? I do my fair share but mostly logging roads and camping. its getting by way of highway to these destinations I am concerned with. I have a 68 Z28 with gearing in the 5s and it racks out serious rpms going down the highway.

Rubimon

Make suure you run with your overdrive off, it will save wear and tear on your tranny. You must be heavy footed, too. I get about 12 with 4.10's but will be going to 5.13's soon.

upnovr

S.O.S.....HELP......I am at my wits end so please no more smart ass comments. No this is not my 1st Jeep its my 4th and I did not buy it to drag race but getting up a simple hill would be nice. I have a 08 Jeep JK with all the add ons to improve performance, upgraded exhaust, air filter, rechipped computer, 456 gear ratio w 35" tires (recommended by 4 Wheel Parts and not for performance), synthetic oil, 91 octain fuel and on and on and on. I have absolutely HATED the performance on this Jeep since day one. Just going up the Bishop incline to Mammoth I am tacking at 5K and going 50mph with ZERO power, head wind in Mojave same thing, pass another vehicle forget it....Cruise America RVs pass my ass like I am sitting still. I jump from 2600rpm to 3500rpm to 5000rpm and back and forth like a pogo stick. Gas milage 10mpg 12 with a tail wind. I can't see how tearing apart the front/rear ends and installing 513s is goig to make that big of a difference. Is there any economical way todrop a real engine in this thing?? i am this much -- from dumping this Jeep and wait until they put a real power train in future models. Let mehear your positive comments.

RSTRICK

I am running 35 Goodyear MT/R auto 5:13 Yukon gears and a Superchips with the 93octane tune. I turn 2350 RPM AT 70 and avg 17-19 MPG. GO 5:13 you won't be sorry.

tempeyeep

I have an unlimited, chip, intake......., i had 35's w/4.88's, and now have 37's with 5.13's. Go 5.13's. My current set up out performs the previous. I was and am getting about 13-15mpg with both set ups. Not using the overdrive on the highway is the only way to go. And getting passed on the highway, that's something your going to have to get used to. Thats why my next buy is a RIPP. And $1600 seems a little steep for gears

snopro269

I just ordered 5.38's for my two door auto Rubicon because it's only 50-100 more rpm's than 5.13's. I have 35 MTR's on stock rims and do mostly trail riding and towing. The final drive on these auto's are so much higher than anything I used to have. So I think you'll be just happier than a lark to go with 5.13's!!
BTW $500 for complete gear set from Northridge and $500 to install gears, sleeved rear, gusseted, and control arm skids.
If I was you I'd get another quote!!

JKOIIIOJK

I am currently running a 07 JKU auto with 35's and 5.13's. The first thing I would buy would be a superchips flashpaq and change your tire size and run it on tow tune. I did that for about six months and it was a big help. Then I would say 1600 is a bit steep for gear change. I paid right around 1000 for mine, Just shop around a little. I then changed to the 5.13's and it was the best money spent yet. I currently get 13.5 around town and up to 16mpg commuting. With the auto dont go 4.88, Definitely 5.13. Any other questions let me know. Hope I could help.