4.10 or 4.56

Re-gear Choice


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floridawolfman

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It's that time. Everyone's suggesting 4.10 and 4.56 gears.
I'm wanting a good daily driver with best mileage, full time OD, seldom off-road

2020 JLU
3.6 manual 6spd

DANA M186 front axle
DANA M220 rear axle
3.45 overall gear ratio
35" tires

(I'm averaging 16.1 combined mileage now with 35")
Looks to me like the 4.10 is closest to my needs. The 4.56 gears are more performance minded for 35"
Any thoughts before I pull the trigger on re-gearing. I only want to do this once.

gear chart.jpg


I want to get this as close to as it was stock regarding rpm's, power, overdrive.

https://tiresize.com/gear-ratio-calculator/

According to the calculator, I need as close to 4.18 to return stock performance. So 4.10 may be slightly sluggish, but 4.56 runs the rpms higher. I live in flat A$$ Florida, not doing any crawling. Occasional mild trails, 98% daily driver.
I know the 4.56 will get more "pep". I want to restore 6th back close to stock as I'm on the interstate 50% of the time and od will help with mileage.
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Jeepjunkie

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I have 4.56 gears and wouldn’t trade them for 4.10s. Also 6speed manual. I only have 33s now, but will go 35s next. The 4.56s are awesome on road and much better offroad too. If anything I wish I did 4.88s for my 35s, but the 4.56s will be good.

At 2500 revs in 6th I hit 72 mph. I expect to hit 75mph with 35s at 2500 revs. 6th is easily useable at speeds of 60 mph or less.
 

Jeepdude101

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If your going to drop the coin go 4:56 the only reason I’m not is because I have a rubicon also a manual and the change from 4:10 to 4:56 isn’t worth it.
 

WhatExit?

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4.88
 

ChattVol

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@floridawolfman I also cared about highway efficiency daily driving a jlu 6 speed with 3.45 gears with 33's for 5k miles and then upgraded to 35s for a week before swapping in rubi axles with 4.10 gearing and lifting 2.5". Drove it on 35s, 2.5" lift and 4.10 gearing for 20k miles and gas mileage was 18-19mpg at 75mph on hwy. 6th gear holds 70+mph on flat hwy and only slight inclines. However, I had to downshift to 4th or 5th quite a bit on the hwy to pass if there was any wind or a hill. If I was paying to regear and cared about highway mileage and knew I was staying on 35s, I'd definitely go 4.56 so you dont have to downshift as often and still maintain solid hwy efficiency. Hope that helps.
 
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floridawolfman

floridawolfman

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I ordered 4.56 yesterday after I filled my tank and felt like I was doing a tractor pull, so added the additional weight up. View attachment 285915
I started thinking about the extra weight.
5 wheels/tires at 115lbs each 575lbs
Hammerhead Front Bumper & Winch 185lbs
21.5 gal gasoline 129lbs (gas weighs 6lbs a gal)
I'm assuming the 3.6 weighs more than the 4
steps ?
889 lbs
more with passenger(s)


Then I realized I need 4.56

my wrangler.jpg
 

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Mr.Fatstacks

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I went back and forth on this for a few days, then just caved in and ordered the 4.56 gear sets. I have a ‘19 Sport manual trans 3.6L on BFG KO2 275/75-17 (measure about 34”, slightly bigger than the same tires in 275/70-17). I probably could’ve gotten away with 4.88s and been happy TBH. I would’ve been able to start in 2nd on the street and use 1st as a granny. I’m happy with the 4.56s, but probably would’ve pulled 4.10s out and sold them.
For what it’s worth I live in the mountains, don’t do a lot of long distance highway driving and don’t really care about fuel economy.
 

OceanBlues

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I went back and forth on this for a few days, then just caved in and ordered the 4.56 gear sets. I have a ‘19 Sport manual trans 3.6L on BFG KO2 275/75-17 (measure about 34”, slightly bigger than the same tires in 275/70-17). I probably could’ve gotten away with 4.88s and been happy TBH. I would’ve been able to start in 2nd on the street and use 1st as a granny. I’m happy with the 4.56s, but probably would’ve pulled 4.10s out and sold them.
For what it’s worth I live in the mountains, don’t do a lot of long distance highway driving and don’t really care about fuel economy.
Let us know how it works out for you.

I have the same engine/transmission as you, however it's an Unlimited, but my math showed I should go with 4.10 when I go up to 35", but honestly even with the stock 31" tires on, I feel like I could use a bigger ratio than the stock 3.45 as I pretty much never use 6th gear and feel like there's already plenty of times I'm having to slip the clutch more than I'd like to get going (especially up hill in reverse).
 

Mr.Fatstacks

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Let us know how it works out for you.

I have the same engine/transmission as you, however it's an Unlimited, but my math showed I should go with 4.10 when I go up to 35", but honestly even with the stock 31" tires on, I feel like I could use a bigger ratio than the stock 3.45 as I pretty much never use 6th gear and feel like there's already plenty of times I'm having to slip the clutch more than I'd like to get going (especially up hill in reverse).
I installed the 4.56s a few months ago and am happy with them, but like I said I probably could’ve gone 4.88 and found it more useful for most of my driving, whereas if I had be chosen 4.10s I would’ve pulled them out and sold them.

I agree, the stock 3.45s aren’t a good fit for the torque characteristics of the 3.6L. I had similar experiences as you. I wouldn’t consider 4.10. I’d say 4.56 or 4.88.
 

Mr.Fatstacks

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With the 4.56s: first is short, but not quite “granny” short. I use it to start off every time, but I’m out if and into second as soon as the rear axle hits the intersection. It’s decently short enough for most of the off-roading I do, whereas with the stock gearing I pretty much wanted to go to 4-low as soon as the pavement ended.
Second is short, but not quite short enough to start off in during regular street driving without slipping the clutch more than I want to. It is good for mall crawlin parking lots.
Third and fourth are good city gears. Fifth will pull most hills on the highway, and sixth is finally useful, but won’t pull many of the hills around where I live (BC interior) at 100km/h (62mph). Can’t remember my revs in 5th or 6th at highway speed, but I’d say I’m usually rollin in 5th when in highway traffic (60ish mph), and get into 6th when I can go a little quicker or hit a flat section of road.
Long winded post!! Hope it benefits someone out there
 

ChattVol

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It's that time. Everyone's suggesting 4.10 and 4.56 gears.
I'm wanting a good daily driver with best mileage, full time OD, seldom off-road

2020 JLU
3.6 manual 6spd

DANA M186 front axle
DANA M220 rear axle
3.45 overall gear ratio
35" tires

(I'm averaging 16.1 combined mileage now with 35")
Looks to me like the 4.10 is closest to my needs. The 4.56 gears are more performance minded for 35"
Any thoughts before I pull the trigger on re-gearing. I only want to do this once.

gear chart.jpg


I want to get this as close to as it was stock regarding rpm's, power, overdrive.

https://tiresize.com/gear-ratio-calculator/

According to the calculator, I need as close to 4.18 to return stock performance. So 4.10 may be slightly sluggish, but 4.56 runs the rpms higher. I live in flat A$$ Florida, not doing any crawling. Occasional mild trails, 98% daily driver.
I know the 4.56 will get more "pep". I want to restore 6th back close to stock as I'm on the interstate 50% of the time and od will help with mileage.
You should consider deleting these gearing charts....they arent accurate for the JL and are misleading. For example, with 4.10's and 37" tires on the 6 speed, it runs 2000rpm @70mph. As @rustyshakelford posted, 37s with 5.13s run 2500 rpm @70mph. According to your chart, it would be running those rpms with 38-39" tires.

The automatic numbers are WAY OFF....about 300-400rpm too high for each tire size.
 
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rustyshakelford

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I went 4.88, and wish I'd done 5.11. I also drive a manual.
I try to share our opinions on gears but they are like arm pits sometimes! Folks need to trust their local shops but sometimes they might not be super experienced with all the combinations available. We’ve done a ton and think we have a decent idea on how to best serve our customers! The manual crowd is much more exclusive and a lot more sensitive to the correct gearing

Brett
 

ChattVol

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I try to share our opinions on gears but they are like arm pits sometimes! Folks need to trust their local shops but sometimes they might not be super experienced with all the combinations available. We’ve done a ton and think we have a decent idea on how to best serve our customers! The manual crowd is much more exclusive and a lot more sensitive to the correct gearing

Brett
Well Brett....after researching regearing for too long and talking with a ton of people who have regeared, regearing shops and MFG's, I ordered Dana 4.88s running 37s with a 6 speed. I dont trailer the jeep to wheelin spots like you do or mainly drive 55-60mph on backcountry Texas roads. I drive 75mph on the HWY to wheelin spots and like the idea of running 2500rpm @75mph and think/hope a 100:1 crawl ratio will idle up steep obstacles. Gearing lower and it seems it could be a negative East Coast wheelin when frequently needing wheel speed to get over obstacles. For driving under 70mph and in Moab where traction is incredible, I can see 5.13s being awesome. I also like that the ring gear has 2 more teeth to make 4.88 slightly stronger.

I spoke with 2 people who are running 6 speed with 40s and 5.13 and they liked it. Who knows...I could've made a mistake...we shall see.
 
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rustyshakelford

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Well Brett....after researching regearing for too long and talking with a ton of people who have regeared, regearing shops and MFG's, I ordered Dana 4.88s running 37s with a 6 speed. I dont trailer the jeep to wheelin spots like you do or drive 55-60mph on backcountry Texas roads. I drive 75mph on the HWY to wheelin spots and like the idea of running 2500rpm @75mph and think/hope a 100:1 crawl ratio will idle up steep obstacles. Any lower than that, it seems it would be a negative East Coast wheelin frequently needing wheel speed to get over obstacles. For driving under 70mph and in Moab where traction is incredible, I can see 5.13s being awesome. I also like that the ring gear has 2 more teeth to make 4.88 slightly stronger.

I spoke with 2 people who are running 6 speed with 40s and 5.13 and they liked it. Who knows...I could've made a mistake...we shall see.
Hey, anything is better than stock and just glad you did go with 4.56;)

Im sure you’ll love the 4.88s!

brett
 
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