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Discussion Starter #1
On a new JK with 35" BFG's auto trans
What would put me closer to stock final drive ratio??
 

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Not sure either will be best. 4.88 will run a little over 2800 rpms at 70mph with 35's for the 2012 model. 4.56 would be a better choice for a daily driver if you can get them but are hard to get in quality gears. So 4.88 may be your best bet if you tow a lot. Might try waiting awhile just to see how it handles but 4.88 should be more then enough.
 

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OutlawJK - Not a lot of real-world data on the 2012s yet. Can you wait for others to get 2012s, re-gear, and give their comments?
 

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NOBODY, knows what will run best in a 2012 right now.... the new 5 speed autos will have a bit of difference in what runs best.....the standard shift may not have changed much..
 

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Not sure either will be best. 4.88 will run a little over 2800 rpms at 70mph with 35's for the 2012 model. 4.56 would be a better choice for a daily driver if you can get them but are hard to get in quality gears. So 4.88 may be your best bet if you tow a lot. Might try waiting awhile just to see how it handles but 4.88 should be more then enough.
:facepalm: Didnt see he was talking about 2012...in that case yes, 4.88 would be better.
 

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It's .83, you can use the manuals chart to get pretty close because 6th gear in the manual is .84

The new Auto can get a pretty good feel for what gears they need from current manual owners and what gears done better for them.

Transmission Gear Ratios:


NSG370 Manual:
R 4.06
1 4.46
2 2.61
3 1.72
4 1.25
5 1.00
6 0.84

W5A580 Auto:
R 3.16
1 3.59
2 2.19
3 1.41
4 1.00
5 0.83
 

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if you plan on wheeling lower is always better
Gonna have to disagree :flowers: ... It depends on your what you're wheeling. It's possible to be geared too low.

T
 

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4.88 is closest to stock. 5.13 gives you a little more power. Id go with 5.13
Not sure I understand what's being asked .... The auto comes standard with 3.73s. If one is trying to match that, just get 4.10s from the factory - 4.10s and 35s match 3.73s and the stock 32s that come on the truck.

T
 

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On a new JK with 35" BFG's auto trans
What would put me closer to stock final drive ratio??
Picking up Tigger tomorrow. 35" Mickey MTZ's and 5:13s gear. Will let you know how it turns out. I previously had the stock gear with 33" Mickey ATZ's. I am interested to see if there is any difference, etc.

Mine is a 2 door '07 JK.
 

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Discussion Starter #15
Comac90 said:
Not sure I understand what's being asked .... The auto comes standard with 3.73s. If one is trying to match that, just get 4.10s from the factory - 4.10s and 35s match 3.73s and the stock 32s that come on the truck.

T
I'm ordering a rubi with 4.10 gears after delivery I'm adding 35" tires and want to re gear to keep my final ratio close to what the 4.10 and 32" tires were

Or maybe a little more to help tow my boat up the hills here in NM
 

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Discussion Starter #16
mgerken1 said:
Picking up Tigger tomorrow. 35" Mickey MTZ's and 5:13s gear. Will let you know how it turns out. I previously had the stock gear with 33" Mickey ATZ's. I am interested to see if there is any difference, etc.

Mine is a 2 door '07 JK.
Does tigger have a manual trans?
Look forward to the results
 

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I'm ordering a rubi with 4.10 gears after delivery I'm adding 35" tires and want to re gear to keep my final ratio close to what the 4.10 and 32" tires were

Or maybe a little more to help tow my boat up the hills here in NM
Okay, gotcha. :thumb:

FWIW, I read over on another site that Dave at AEV has driven the auto with 4.10s and 35s and said it was perfectly good. Granted, he wasn't referring to towing. But, it may be worth driving it first before dropping the cash ...

T
 

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Discussion Starter #18
Comac90 said:
Okay, gotcha. :thumb:

FWIW, I read over on another site that Dave at AEV has driven the auto with 4.10s and 35s and said it was perfectly good. Granted, he wasn't referring to towing. But, it may be worth driving it first before dropping the cash ...

T
Yeah I spoke with Dave and he told me the same thing
What I find interesting is that with the 2011 he recommended 5.13 gears???

I'll get on the gear calculator tomorrow
And see how it works out on paper
 

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Yeah I spoke with Dave and he told me the same thing
What I find interesting is that with the 2011 he recommended 5.13 gears???

I'll get on the gear calculator tomorrow
And see how it works out on paper
Different motor between the 12 and the 11. Makes all of the difference. I think the new ones are 280 or something. I sure I will be corrected.
 

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Yeah I spoke with Dave and he told me the same thing
What I find interesting is that with the 2011 he recommended 5.13 gears???

I'll get on the gear calculator tomorrow
And see how it works out on paper
The 2012 is a whole other beast. Between the increase in HP and torque, the much flatter torque curve and the new 5-spd auto which is geared much lower, you can get away with much higher axle diff gears.

T
 
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