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I have the 4.0L auto with 31" tires... Not sure the gearing, either 3.07 or 3.73... Anyway I was told to get 4.11 gears to get more power. My question is, what does re-gearing do and is it really worth the cost??

I've spent alot of money on crap like air intake, throttle body, stuff that really doesn't do jack for ya... don't want to waste more money on junk
 

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I have the 4.0L auto with 31" tires... Not sure the gearing, either 3.07 or 3.73... Anyway I was told to get 4.11 gears to get more power. My question is, what does re-gearing do and is it really worth the cost??

I've spent alot of money on crap like air intake, throttle body, stuff that really doesn't do jack for ya... don't want to waste more money on junk
i've heard a lot of people drive around with lets say 33's and 3.73's and they said that they would think "its not that bad" but when they regeared it made a huge difference. regearing basically restores the power you lose when installing bigger tires. if you lost 5th or 6th gear it will restore it to where you can use your higher gears without struggling. it will bring it back much closer to how it was stock.
 

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i've heard a lot of people drive around with lets say 33's and 3.73's and they said that they would think "its not that bad" but when they regeared it made a huge difference. regearing basically restores the power you lose when installing bigger tires. if you lost 5th or 6th gear it will restore it to where you can use your higher gears without struggling. it will bring it back much closer to how it was stock.
I have 33's and 3.73 gears on my LJ. I also have a 4 speed auto transmission. I only noticed a slight difference in available power when I went to the 33's, and I can cruse on the freeway at 80mph without any problems.

A friend has a '05 LJ with the same engine, trans, and tires as mine. He spent the money and bumped his gears up to 4.11's. I've driven it and can't really say there is a noticeable difference.

Conversely, another friend has a '03 TJ X with a 6 speed manual transmission and 3.73 gears. When he went to 33's, he lost 6th gear and most of 5th as well. I hate driving his Jeep on the highway. He's talking about re-gearing and going to 35's at the same time. It will be interesting to see the result.
 

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I have the 4.0L auto with 31" tires... Not sure the gearing, either 3.07 or 3.73... Anyway I was told to get 4.11 gears to get more power. My question is, what does re-gearing do and is it really worth the cost??
Y0u prolly hav the 3.07's like mine... unless you have a D44, then you might have the 3.73's. What a re-gearing does is reconfigure your drive ratios to match the size of the tire that your vehicle is running. Notice that your Jeep revs a little higher a highway speeds now with the larger tires? Re gearing it will drop that rev and take a little stress off your motor. BUt once you get to 33" tires a re-gear is deffinatly something to look at.
 

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I have 33's and 3.73 gears on my LJ. I also have a 4 speed auto transmission. I only noticed a slight difference in available power when I went to the 33's, and I can cruse on the freeway at 80mph without any problems.

A friend has a '05 LJ with the same engine, trans, and tires as mine. He spent the money and bumped his gears up to 4.11's. I've driven it and can't really say there is a noticeable difference.

Conversely, another friend has a '03 TJ X with a 6 speed manual transmission and 3.73 gears. When he went to 33's, he lost 6th gear and most of 5th as well. I hate driving his Jeep on the highway. He's talking about re-gearing and going to 35's at the same time. It will be interesting to see the result.
There's just not enough of a difference from 3.73 to 4.11 to notice really. Especially with an auto. With a manula you might notice a little bit. I'm running 3.73's with my 35's and auto trans and I like it. Plenty of power unless I'm driving in the mountains. With my TeraLow in there it still has a great crawl ratio, but won't overpower the brakes. If I was in my diff's I might change them over to 4.10's, but only if I was in there anyway and would probably just put some used stuff in it. Otherwise if you are re-gearing to correct from larger tires then you should go to at least 4.56 if you have an auto.
 

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On my '06 "X" trim
The gears are 3.73
Automatic
Tires are the P225/75R15
 

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I have 33's and 3.73 gears on my LJ. I also have a 4 speed auto transmission. I only noticed a slight difference in available power when I went to the 33's, and I can cruse on the freeway at 80mph without any problems.

A friend has a '05 LJ with the same engine, trans, and tires as mine. He spent the money and bumped his gears up to 4.11's. I've driven it and can't really say there is a noticeable difference.
thats what others said too. they could cruise fine on freeway and it wasn't too bad but the regear made a difference. i don't think going from 3.73 to 4.11 is a big difference. maybe if he would have went to 4.56. most of the people that said this went from 3.73's or 3.07's to 4.56 so the difference was bigger for them rather than a smaller difference in 3.73 to 4.11. i cruise fin in mine also but i hear people that went with 4.10's and 33's sayin they wish they woulda went 4.56

no experience with new gears but i tell ya i wish i could go to 4.10's. that'd be pretty sweet with my 32's. and i think i'd notice a difference coming from only 3.07's.
 

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Normally the 05 & 06 Wrangler X model with auto transmission came with the 373 gears.
 

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Discussion Starter · #13 ·
with that info, i went out and checked the tag that i didnt know was afixed the the diff cover until now and found it has the 3.73 gears. thanks.

now i need to knwo the overdrive ratio in the stock 4 speed auto so i can figure out my rpm/mph change at a given time wioth a given tire diameter.

i am thinking of running a 30x9.5x15 tire right now

steve
 

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Discussion Starter · #15 ·
i dont go out much in it so i dont think my purchasing a 31 or more tire would do me anything.

30 will be fine for now and when the time comes ill upgrade everything from there.

whats the stock 215 series tire in height? i tought it was 28 inches.

steve
 

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My question is, what does re-gearing do and is it really worth the cost??
Think of regearing as a line like the games you find around.

Acceleration |---------------[O]-------------| Top speed

The bigger number gears you put on there you move that button [O] towards acceleration but loose top speed. You are now probably thinking oh well top speed in jeep who cares about it. It will increase the cruize rpm which might in fact change your gas milage. Higher gearing will reise your cruize rpm than you have now but you cannot for sure say it will decrease your mpg just because of higher rpm though. Every engine has Ideal cruize rpm and below or above it you will get worse mpg. I personally believe this rpm for the 4.0 is around 1400-1500 rpm but again this is just my gues. If you dont care about getting just a bit worser mpg than you already get i would say its worth it.

If you put bigger tires that button automatically moves towards top speed and you loose acceleration. When you replace the gearing with higher # proper gearing (higher the gearing the more acceleration as long as the engine alows it) your acceleration restores or get somewhat better than stock.
 
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