Tufelhundin

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@j.o.y.ride

yes... 8th gear. Look by the “D”

with 4.56 it will go in 8th at 45mph, I haven’t paid much attention less than





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j.o.y.ride

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@j.o.y.ride

yes... 8th gear. Look by the “D”

with 4.56 it will go in 8th at 45mph, I haven’t paid much attention less than
Got it. I will check my current gearing at 70 tomorrow in 8th. I was at 19xx for 80mph so I imagine it will be very unhappy in 8th that speed as is on my truck.
 

Tufelhundin

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Got it. I will check my current gearing at 70 tomorrow in 8th. I was at 19xx for 80mph so I imagine it will be very unhappy in 8th that speed as is on my truck.

As mentioned in my post above with the picture that you quoted, Grimmjeeper showed I that I should be running 2091rpm @ 70mph. The picture shows me right at 2100rpm...so very close.

@80 it states that I should be @ 2390rpm and I believe that to be about the same as I was as well, for my memory says I was showing around 2400-2500rpm.


Some food for thought, I was running 3.73's with the 315/70-17's originally and at 65-70 I could put it in 8th manually but it would drop back into 6th or 7th as soon as I put it back in drive....it didn't like it at all.

Grimmjeeper shows with 3.73's @70mph / 1711rpm and @65mph it shows 1588rpm...the rpm at 65 was pretty much spot on for I run 65mph every day and with 3.73 it pretty much stayed in 6th and sometimes 7th if I had a slight tail wind or a downward slope in the road.


Another slight observation I have made, reverse seems to be much better now and when I back out on the road from my driveway the jeep is facing uphill on the road....so when I had 3.73's and I would put it in drive the jeep would start to roll backwards between the time I let off the brake and started to push the skinny peddle. With the new gearing I cant make it roll backwards, I can put it in drive and completely let go of the brake and it just sits there. Just something Ive noticed, I didn't think the gearing would change anything in that matter but it certainly seems to.
 

Socks

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Several people asked me to post my experience with 4.56 gears, so here it is. I've got a 2021 Gladiator Overland, 3.6L V6 with manual transmission, which came with the 3.73 gears. A couple of months ago I added a Mopar 2" lift and 35 inch mud terrain tires. Last week, I had the gears swapped to 4.56. My goal for my build was to get a perfect blend between (1) a pretty darn nice daily driver truck (I came from a F150) and (2) a respectably offroad capable real Jeep. I think I have now achieved exactly that and I absolutely love the way it turned out:

Why I regeared: As soon as I added the lift and bigger tires, while still running the 3.73 gears, my truck felt severely under-powered. My gas mileage dropped from 17 mpg city/20 mpg highway to about 12 mpg no matter where I was driving. First gear starts became WAY more prone to stalling and felt very sluggish. On the highway, 5th and 6th gear became nearly useless--no power, no ability to maintain speed or pass in 5th or 6th, and constant downshifting. At 70 mph I was hitting about 2,000 rpm in 6th gear. If I hit even the slightest incline or wind, I could have the throttle completely opened up and would still be losing speed. I drive across Texas a lot, and through the Hill Country here in particular, so this was just intolerable for me.

Why I chose 4.56: I first thought about 4.10s. I talked to several "jeep people" online and in person, and everyone said regearing to 4.10 would be a waste of time and that I should be considering 4.56 or 4.88. So then I went back and forth between 4.56 and 4.88 a lot--reading forums about different experiences with each (mainly on the JL platform though--not as much info out there on the manual trans JTs), etc. I even changed my regear order back and forth a couple of times.

My main focus was increasing the RPMs in top gear back into the natural power band of the 3.6L V6 and restoring the fuel efficiency, but I also wanted a little more offroad performance vs my stock setup. The offroad shop that did the work estimated that with 4.56 gears in 6th gear at 75 mph, I would hit 2400-2500 RPM, and that would increase to 2600-2700 RPMs with 4.88s. The 4.88 option sounded like I would be running the engine a little harder than I wanted, but really would have been fine for the vehicle, and it would definitely have a lot of power. But first gear also would probably be really short with the 4.88s, and a lot of JL folks said their rides just felt a little too "tall" with the 4.88s and 35s.

Ultimately I went with the 4.56, which I determined would be just slightly over-geared compared to a stock Rubicon or Max Tow Sport (both have 4.10s) and would get the RPMs in a really good sweet spot on the highway... which sounded like exactly what I was going for.

After the regear: I just finished my 500-mile, grandma-driving break-in period on the new gears and had the gear oil drained and refilled. Now that I can drive normally again, my gas mileage has improved noticeably--roughly 17-18 mpg in the city and I've gotten similar results on short highway drives. Additionally, throughout 1st-6th gear there is significantly more power. My truck is noticeably peppier than stock off the line, and starts are much easier... let out the clutch and the truck does most of the work. 1st is quick and full of torque, but not so much that it feels like I'm driving a tractor... feels more like the power you'd get in a V8 full-size truck off the line. 5th and 6th gear maintain speed on the highway with absolutely no problem, even in hills and wind.. with no downshifting needed so far. I can accelerate to pass in 6th (which I could barely do even before the lift & tires). I'm at exactly 2,500 rpms at 75mph which feels perfect on this engine. It will be so nice to have functional cruise control in this thing now!

I'm taking it to Moab pretty soon and will report back on the long-drive and offroad experience, but so far the 4.56 seems to be the absolute sweet spot.... a little sportier feeling than a stock rubicon, but not so much that it feels like a weekend-only vehicle. Fuel efficiency is respectable so far, and it's very responsive and powerful through all gears. Feels to me like 4.88s would have been a little too much for what I was going for, and so far couldn't be happier with the pairing of 4.56s on 35 inch tires.

IMG_4286.JPG
IMG_4314.JPG
Great looking Gladiator! Has a nice balanced look to it. What tires and wheels are you using and what size.
 

SelfmodJT

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Several people asked me to post my experience with 4.56 gears, so here it is. I've got a 2021 Gladiator Overland, 3.6L V6 with manual transmission, which came with the 3.73 gears. A couple of months ago I added a Mopar 2" lift and 35 inch mud terrain tires. Last week, I had the gears swapped to 4.56. My goal for my build was to get a perfect blend between (1) a pretty darn nice daily driver truck (I came from a F150) and (2) a respectably offroad capable real Jeep. I think I have now achieved exactly that and I absolutely love the way it turned out:

Why I regeared: As soon as I added the lift and bigger tires, while still running the 3.73 gears, my truck felt severely under-powered. My gas mileage dropped from 17 mpg city/20 mpg highway to about 12 mpg no matter where I was driving. First gear starts became WAY more prone to stalling and felt very sluggish. On the highway, 5th and 6th gear became nearly useless--no power, no ability to maintain speed or pass in 5th or 6th, and constant downshifting. At 70 mph I was hitting about 2,000 rpm in 6th gear. If I hit even the slightest incline or wind, I could have the throttle completely opened up and would still be losing speed. I drive across Texas a lot, and through the Hill Country here in particular, so this was just intolerable for me.

Why I chose 4.56: I first thought about 4.10s. I talked to several "jeep people" online and in person, and everyone said regearing to 4.10 would be a waste of time and that I should be considering 4.56 or 4.88. So then I went back and forth between 4.56 and 4.88 a lot--reading forums about different experiences with each (mainly on the JL platform though--not as much info out there on the manual trans JTs), etc. I even changed my regear order back and forth a couple of times.

My main focus was increasing the RPMs in top gear back into the natural power band of the 3.6L V6 and restoring the fuel efficiency, but I also wanted a little more offroad performance vs my stock setup. The offroad shop that did the work estimated that with 4.56 gears in 6th gear at 75 mph, I would hit 2400-2500 RPM, and that would increase to 2600-2700 RPMs with 4.88s. The 4.88 option sounded like I would be running the engine a little harder than I wanted, but really would have been fine for the vehicle, and it would definitely have a lot of power. But first gear also would probably be really short with the 4.88s, and a lot of JL folks said their rides just felt a little too "tall" with the 4.88s and 35s.

Ultimately I went with the 4.56, which I determined would be just slightly over-geared compared to a stock Rubicon or Max Tow Sport (both have 4.10s) and would get the RPMs in a really good sweet spot on the highway... which sounded like exactly what I was going for.

After the regear: I just finished my 500-mile, grandma-driving break-in period on the new gears and had the gear oil drained and refilled. Now that I can drive normally again, my gas mileage has improved noticeably--roughly 17-18 mpg in the city and I've gotten similar results on short highway drives. Additionally, throughout 1st-6th gear there is significantly more power. My truck is noticeably peppier than stock off the line, and starts are much easier... let out the clutch and the truck does most of the work. 1st is quick and full of torque, but not so much that it feels like I'm driving a tractor... feels more like the power you'd get in a V8 full-size truck off the line. 5th and 6th gear maintain speed on the highway with absolutely no problem, even in hills and wind.. with no downshifting needed so far. I can accelerate to pass in 6th (which I could barely do even before the lift & tires). I'm at exactly 2,500 rpms at 75mph which feels perfect on this engine. It will be so nice to have functional cruise control in this thing now!

I'm taking it to Moab pretty soon and will report back on the long-drive and offroad experience, but so far the 4.56 seems to be the absolute sweet spot.... a little sportier feeling than a stock rubicon, but not so much that it feels like a weekend-only vehicle. Fuel efficiency is respectable so far, and it's very responsive and powerful through all gears. Feels to me like 4.88s would have been a little too much for what I was going for, and so far couldn't be happier with the pairing of 4.56s on 35 inch tires.

IMG_4286.JPG
IMG_4314.JPG
Did you upgrade the clutch? Also, if you went with a magnuson supercharger would you have chosen the same gearing? Asking because i plan to do everything you did but also a supercharger.
 

Chaosmtb

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@Tufelhundin the better gear gives you more leverage over the tires, engine braking and (if manual) engine hold in gear while off is increased. The auto does benefit in manual mode the forced down shift and engine braking is really good w this 8 speed.
 

PDiddy

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I am running 4:88 with my 35s. I went this route because I tow travel trailer and wanted to gain some torque. I still need to have the computer told it has different gears and tire size. So I can't say for sure what the RPMs are at 70. Right now it says 2250ish. But I also don't know if I am actually going 70. I got to get into jeep for the programming.

It is super fun to drive. very responsive. 4L is very low now. lots of torque. I have not towed with it yet, but it should be better than stock with 33s.

I would also mention that tire weight makes a big difference too. Two people could have 5-10lbs difference per tire for the same size. And that will make a big difference in performance. Rims too. I stayed with my stock rims to save weight.
 

BAT

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So are people running 35's on 4:10 gears finding its not working out and having to regear. I had planned to eventually move to 35's on my Max Tow but if have to do all of this regearing, etc to get the proper performance it will likely end up staying on 33's.
 

Tufelhundin

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@BAT

I believe some are re-gearing due to towing heavier loads and doing so at elevation or some are eventually planning to go to 37's as well. However most are staying at 4.10 with 35's and the JT's are doing quite well. If I had 4.10's "with my auto" I would have not changed my gearing. I originally had 3.73's with 315/70-17's not sure why they put that gearing on them...I truly dont believe there was any benefit even stock....the max tows still seemed to get better mpg's for they stay in 8th...anyway I figured if I was going to spend that kind of money to go a step past a stock max tow , I believe Im running around 50rpm more at 65mph than a max tow with stock tires.
 
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DanW

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Several people asked me to post my experience with 4.56 gears, so here it is. I've got a 2021 Gladiator Overland, 3.6L V6 with manual transmission, which came with the 3.73 gears. A couple of months ago I added a Mopar 2" lift and 35 inch mud terrain tires. Last week, I had the gears swapped to 4.56. My goal for my build was to get a perfect blend between (1) a pretty darn nice daily driver truck (I came from a F150) and (2) a respectably offroad capable real Jeep. I think I have now achieved exactly that and I absolutely love the way it turned out:

Why I regeared: As soon as I added the lift and bigger tires, while still running the 3.73 gears, my truck felt severely under-powered. My gas mileage dropped from 17 mpg city/20 mpg highway to about 12 mpg no matter where I was driving. First gear starts became WAY more prone to stalling and felt very sluggish. On the highway, 5th and 6th gear became nearly useless--no power, no ability to maintain speed or pass in 5th or 6th, and constant downshifting. At 70 mph I was hitting about 2,000 rpm in 6th gear. If I hit even the slightest incline or wind, I could have the throttle completely opened up and would still be losing speed. I drive across Texas a lot, and through the Hill Country here in particular, so this was just intolerable for me.

Why I chose 4.56: I first thought about 4.10s. I talked to several "jeep people" online and in person, and everyone said regearing to 4.10 would be a waste of time and that I should be considering 4.56 or 4.88. So then I went back and forth between 4.56 and 4.88 a lot--reading forums about different experiences with each (mainly on the JL platform though--not as much info out there on the manual trans JTs), etc. I even changed my regear order back and forth a couple of times.

My main focus was increasing the RPMs in top gear back into the natural power band of the 3.6L V6 and restoring the fuel efficiency, but I also wanted a little more offroad performance vs my stock setup. The offroad shop that did the work estimated that with 4.56 gears in 6th gear at 75 mph, I would hit 2400-2500 RPM, and that would increase to 2600-2700 RPMs with 4.88s. The 4.88 option sounded like I would be running the engine a little harder than I wanted, but really would have been fine for the vehicle, and it would definitely have a lot of power. But first gear also would probably be really short with the 4.88s, and a lot of JL folks said their rides just felt a little too "tall" with the 4.88s and 35s.

Ultimately I went with the 4.56, which I determined would be just slightly over-geared compared to a stock Rubicon or Max Tow Sport (both have 4.10s) and would get the RPMs in a really good sweet spot on the highway... which sounded like exactly what I was going for.

After the regear: I just finished my 500-mile, grandma-driving break-in period on the new gears and had the gear oil drained and refilled. Now that I can drive normally again, my gas mileage has improved noticeably--roughly 17-18 mpg in the city and I've gotten similar results on short highway drives. Additionally, throughout 1st-6th gear there is significantly more power. My truck is noticeably peppier than stock off the line, and starts are much easier... let out the clutch and the truck does most of the work. 1st is quick and full of torque, but not so much that it feels like I'm driving a tractor... feels more like the power you'd get in a V8 full-size truck off the line. 5th and 6th gear maintain speed on the highway with absolutely no problem, even in hills and wind.. with no downshifting needed so far. I can accelerate to pass in 6th (which I could barely do even before the lift & tires). I'm at exactly 2,500 rpms at 75mph which feels perfect on this engine. It will be so nice to have functional cruise control in this thing now!

I'm taking it to Moab pretty soon and will report back on the long-drive and offroad experience, but so far the 4.56 seems to be the absolute sweet spot.... a little sportier feeling than a stock rubicon, but not so much that it feels like a weekend-only vehicle. Fuel efficiency is respectable so far, and it's very responsive and powerful through all gears. Feels to me like 4.88s would have been a little too much for what I was going for, and so far couldn't be happier with the pairing of 4.56s on 35 inch tires.

IMG_4286.JPG
IMG_4314.JPG
Looks like you nailed it! I likely won't regear with the lighter JLUR and current 4.10 gearing, but if I did, I've thought 4.56 would be the sweet spot and the rpms in 6th would be similar to that of the JK's six speed, which I think is better for that gear. I won't do it because 6th gear is the only place I would want it, and it is perfect in all other gears. But if I do get a wild hair and go for it, 4.56 will be the deal.

Btw, that Jeep looks GREAT!

When are you going to Moab? We're going during Easter Jeep Safari week, arriving on the 27th or 28th of March and staying until April 2. We've got my JL, my brother's Gladiator, and at least one JK going, possibly 2.
 

DanW

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So are people running 35's on 4:10 gears finding its not working out and having to regear. I had planned to eventually move to 35's on my Max Tow but if have to do all of this regearing, etc to get the proper performance it will likely end up staying on 33's.
I can't speak for the Gladiator, but I'm fine with it in my JLUR/manual. But I will note that I've got stock rims with KO2's, and that combo is very light. I agree with @PDiddy that lighter tires/rims help. But If I had a Gladiator, which is a little heavier, and towed heavier things than my fishing boat, I'd certainly consider 4.56 gears. When I tow, I can just run 5th gear and its ratio is the same as the JK's 6th, so no problem there.

I'd say get the lift/tires and drive it for awhile with the 4.10 gearing. When I sit and read these threads, I start thinking about doing it but when I go drive the Jeep, I quickly realize I've got no need to go up from there. Unless I lived in the mountains, maybe.

My brother has heavier 35's with his Gladiator Rubi and the auto and it does fine. He has no complaints. But when he tows his boat, which loaded, is just under the maximum tow rating, his mileage drops through the floor. I think he'd benefit from 4.56 gearing or even 4.88. But he's got a big new Chevy HD with a Duramax, so no need to worry about it. He loves the power in the Gladiator otherwise with the 4.10s and auto.
 

PDiddy

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If I wasn’t towing a travel trailer, I would not have regeared. 4:10 was plenty for 35s. I think I would have only considered regearing with 37s.

my 35s are only 3lbs heavier than stock ones, and I’m running stock rims. I could not feel that weight gain difference. The thing I could feel was the steering. It felt a little heavier because added grip. You get used to that in the first day and don’t notice it anymore.

shameless photo of my Gladiator on 35s...



A86897D6-F31C-4685-A9D3-FF4BD18384F5.jpeg
 
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mrmo

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If I wasn’t towing a travel trailer, I would not have regeared. 4:10 was plenty for 35s. I think I would have only considered rehearing with 37s.

my 35s are only 3lbs heavier than stock ones, and I’m running stock rims. I could not feel that weight gain difference. The thing I could feel was the steering. It felt a little heavier because added grip. It you get used to that in the first day and don’t notice it anymore.

shameless photo of my Gladiator on 35s...



A86897D6-F31C-4685-A9D3-FF4BD18384F5.jpeg
Looks good, are those tires 35x12.50's or the 11.50's ? Im planning on the same, didnt know if the stock wheels would work w stock baxkapacing and 12.50 width tires
 

ClunkyJeep

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The OP is talking about a manual transmission which has taller gears than the 8 speed auto. Seems like a lot of back and forth in this thread. Hard to compare gears and tires between the 2 transmissions.

There are calculators out there that show how an increase in tire size changes your effective gear ratio and what you need to get it back to stock. If changing gears once you know what it takes to get back to stock you can go lower or higher depending on what you want. Wider tires or terrain may affect what you feel as well. My 4.10 rear end dropped to an effective rate of about 3.9 after going from 33s to 35s. The tire is taller but not wider so no extra resistance. I also kept an all terrain instead of a going to a mud terrain. I cruise at 75 about 2000 rpm on highway and plenty of pep in the low gears.
 
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