dustinc83

i put 35X12.50r17 mtr with kevlar tires on my 2007 4 door jk X Auto with 4:10 gears....

Question 1. i have 4:10 gears. is it necessary to change gears?? I feel a little loss of power but nothing that is holding back.. But over time will the 4:10 hurt my tranny?

( my rpm's at 75 are 2000-2100, I like that for the sake of gas savings)


Questions 2. if i do change gears to 4:88 would it improve my MPG's or am i better off staying with the 4:10 for better MPG??

Questions 3. What do u guys think of putting in a cold air intake and new exhaust?
would add back my loss of power and also would it give me better mpg's??



I ask about the mpg's cuz i go on long trips. 85% daily driver 15% off road

Smerny

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JayhawkJeep

1. It is not necessary to change gears. If you are happy with what you got I wouldn't do it.

2. I went from 3.73 gears to 5.13's and I am seeing a jump of about 2.5 MPG

3. The number one thing to do to give you your pep back is regear. Next option would be a programmer then exhaust and cold air intake.

Edit:

If a shop is quoting 2600 to regear you need to shop around

roadking54

I'm also interested in the answers to all your re-gear questions.

At a minimum, I would suggest the Superchip Flashpaq. I recently added 35x12.5 tires and a lift and only have 3.73 gears w/ my auto unlimited....it's a lot better then I thought it would be and quite drivable under all conditions!

GoodysGotaCuda

Complete regears can be done for $1000 and less. $2600?! holy crap! At least get 2-3 JKs regeared for that

redrockin7

For 2,600, heck no... that's outrageous.

For 1,300 going market rate for parts and labor on both axles, heck yes... best thing I've done to my JK since 35s.

I would not bother with intake and exhaust, get a programmer and/or re-gear before wasting that $.

dustinc83

Did u lose 2.5 mpg with 3:73 then gained it back with new gears or did ur mpg stay the same with 3:73 then got even better mpg with gears??

JayhawkJeep

Millage went down when I went 35's. Then went up when I regeared. I would say I getting about what I did when I was stock, maybe a little better.

redrockin7

You shouldn't have gotten 35s if you are this worried about mileage... it will be lower than stock with 30s or 32s no matter what gears you have.

Most people with 35s and the re-gear to lower gears (4.88-5.13) get worse mileage than a stocker, but still acceptable (I get 15 town, 17 highway for example with my 5.13s, but I got 17 and 19 stock with 32s and 3.73).

Most people with 35s and higher gears like stock 3.21, 3.73 or 4.10 get worse than a non-regeared JK. Say 12-14 MPG on 35s and stock gears. 4.10 is your best stock set of course and you might do a little better than this but the 3.xx gears suck with 35s and you will get $hit for mileage. 4.10 you won't get exceptional mileage either unless you can ALWAYS drive 75MPH....

There are exceptions of course, but this is the general rules of thumb I've seen in the majority of JKs.

dustinc83

What does that progammer/ superchip do??

I have the procal that came with my lift.


I know 35's will lack in mpg's. I just like to know I got what it take when need be. My first car was a 97 jeep tj 2.5l. So for ten years I lack power I couldn't do anything with it. So u can say I went a little over board now. I'm just try to get the best mpg posable, that's all