Need help shopping for new gears

LCL-Dead

It broke.. ..again
Supporting Member
Mar 21, 2017
151
Havelock, NC
Hey there guys and gals,

RE 3.5" lift + 33" tires on an otherwise stock Rubicon. I'm looking to gear up to 4.56 to get some of my fuel economy (stop laughing) back, as well as a better ability to maintain 60mph without having to kick the OD off or settle for 55 or 75 depending on if I want it on or not.

My question is pretty simple:

Carriers. Do I need to replace the factory carrier front and rear as well, should I? This thing hasn't seen any major offroad action since before I threw the lift on due to parts and maintenance issues so it won't be getting harassed in the near future (namely because I'm still cutting off parts of the old suspension every weekend).

I appreciate any info you guys/gals can toss my way.
 

nk24

Wrenching one four-letter word at a time...
Supporting Member
Jul 6, 2017
229
Phoenix
You'll want to regear to 5.13 for your 33" tires and auto transmission. Going from 4.10 to 4.56 won't be worth the cost.

I believe the carrier break for the Dana 44 is 3.73/3.92, so you shouldn't need a new carrier. Calling @Rob5589 for confirmation.
 
Reactions: LCL-Dead

Pzilly

Member
Supporting Member
I agree, 4.88 or 5.13 is correct w the auto due to steep OD. I am currently at odds w which to go myself, some owners are reporting a mystery front end vibration w the 5.13 gear set according to a supplier I spoke with, this seems to be a small amount of people, then again I'm usually that lucky small percentage.... looking at posts on here his statement seems to be true, I have only found 1 confirmed case using the 4.88,having this issue, but i really want the 5.13, it's not our DD but it is fun once in awhile to tow the jet skis w the LJ jeep and while I am sure the 4.88 would do it, I'd prefer the 5.13...
 
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OP
LCL-Dead

LCL-Dead

It broke.. ..again
Supporting Member
Mar 21, 2017
151
Havelock, NC
I appreciate the feedback gents. Had no idea the steep OD warranted such a severe step-up in ratios. That would've been a regretful purchase.

As its an everyday driver (13 miles to work one way) how would you assume the 4.88/5.13 would effect low end acceleration and fuel consumption?
 
Reactions: Jerry Bransford

Chris

Administrator
Staff Member
Sep 28, 2015
34,475
Salem, Oregon
Even with the proper gears, you won't get rid of that annoying hunting for OD, I promise.

I have 5.38 gears in mine with 35s and the 42RLE transmission, and it still hunts for overdrive. It's not quite as bad as it was with 4.10 gears, but it's far from perfect.

You'll get better fuel economy though with the new gears, and much better power.
 
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AndyG

TJ Addict
Supporting Member
Jul 30, 2018
1,542
Alabama
Now that you have your ratio, The Forum regearing committee meets the 20th so you will need to submit all the necessary paperwork and don't forget your VIN number, a copy of your bank statement to support future upgrades, photograph of the vehicles odometer, and don't forget the proof of purchase for the larger tires.

If it's approved you have 60 days to get the work done.
 

Jerry Bransford

TJ Guru
Supporting Member
Nov 9, 2015
9,461
Escondido California
I agree, 4.88 or 5.13 is correct w the auto due to steep OD. I am currently at odds w which to go myself, some owners are reporting a mystery front end vibration w the 5.13 gear set according to a supplier I spoke with,
That's the first time anyone has mentioned a front-end vibration strictly from the choice of 5.13 gearing in any of the several Jeep forums I follow. Any vibration is more likely from an improper front pinion angle than the actual specific 5.13 gear ratio itself. When that's the case it can usually be dialed out by correcting the pinion angle. I wouldn't hesitate going with 5.13 at all for 33" tires, I went to 5.38 for my 35" tires.
 
Reactions: Jon Wildes
OP
LCL-Dead

LCL-Dead

It broke.. ..again
Supporting Member
Mar 21, 2017
151
Havelock, NC
Even with the proper gears, you won't get rid of that annoying hunting for OD, I promise.

I have 5.38 gears in mine with 35s and the 42RLE transmission, and it still hunts for overdrive. It's not quite as bad as it was with 4.10 gears, but it's far from perfect.

You'll get better fuel economy though with the new gears, and much better power.
See, I don't quite hunt for OD (if I'm assuming the correct thing when you say "hunt for it"). With OD on it'll kick into OD around 50mph but my issue is the speed limit is 55 and traffic generally goes 70, so I shoot for about 60 to fit into the middle of that mishmash of idiots.

With OD on, I struggle to get to 60 or I have to floor it to get it to downshift, but then it gets to 60, drops back into the OD gear and struggles to maintain it.

With OD off I'll set my cruise control at 55-57 on the speedometer and maintain that at about 2600rpm. I just want it to not struggle to maintain 60 with OD on.
 

BuildBreakRepeat

Garrett Hoover
Supporting Member
Jan 21, 2019
107
Corvallis, Oregon
See, I don't quite hunt for OD (if I'm assuming the correct thing when you say "hunt for it"). With OD on it'll kick into OD around 50mph but my issue is the speed limit is 55 and traffic generally goes 70, so I shoot for about 60 to fit into the middle of that mishmash of idiots.

With OD on, I struggle to get to 60 or I have to floor it to get it to downshift, but then it gets to 60, drops back into the OD gear and struggles to maintain it.

With OD off I'll set my cruise control at 55-57 on the speedometer and maintain that at about 2600rpm. I just want it to not struggle to maintain 60 with OD on.
And that my friend is the beauty of regearing! It allows you to run 60mph with OD on and have the right engine RPM to maintain that speed. And if you’re towing or doing hills/inclines it will actually improve your MPG!
 
Reactions: Jerry Bransford

pagrey

TJ Enthusiast
Apr 10, 2018
170
Los Angeles, CA, USA
First, might get vibes, thousand of dollars to fix vibes. Might ask Jerry why he just replaced his driveshaft, I'm sure it was unrelated.
Second, 5.13 will force you to deal with that horrible overdrive everyday. Getting on the freeway your Jeep will be slower than it is now when it shifts out of third gear because your current Jeep can stay in third to much higher speeds. This means your passing power at 60 will be reduced, just simple math.
Third, you can just hit the o/d button and have almost the same final drive without thfat horrible o/d gap.
Do what makes you happy but don't let anybody sweep the details under the rug. There are big upsides on the trail but there are other things to consider. Read threads, when people like Chris just resort to name calling there might be more to the story.
 

Pacoson71

New Member
Jan 27, 2019
4
MA
I'm waiting for Revolution G&A to get more 5.38s in the country, (3/11)
Question,
Having 33s now but maybe uping to 35s......
Is 5.38s too much for 33s?
Grimms calc seems ok but , real world knowledge I seek too.
Ty
 

Chris

Administrator
Staff Member
Sep 28, 2015
34,475
Salem, Oregon
See, I don't quite hunt for OD (if I'm assuming the correct thing when you say "hunt for it"). With OD on it'll kick into OD around 50mph but my issue is the speed limit is 55 and traffic generally goes 70, so I shoot for about 60 to fit into the middle of that mishmash of idiots.

With OD on, I struggle to get to 60 or I have to floor it to get it to downshift, but then it gets to 60, drops back into the OD gear and struggles to maintain it.

With OD off I'll set my cruise control at 55-57 on the speedometer and maintain that at about 2600rpm. I just want it to not struggle to maintain 60 with OD on.
Hunt is probably the wrong word. I just mean to say that even with 5.38 gears, OD still comes on much sooner than it should, which is just the inherent nature of that stupid .69 OD gear.

Don't get me wrong, it's much better to drive with 5.38 gears than it was with 4.10s, I'm just saying that it's still nowhere near perfect. But, we can blame the a**holes at Chrysler for sticking a front wheel drive designed transmission in a vehicle (our Jeeps) that it never belonged in to begin with.
 

Rob5589

Certified video trained differential rebuilder
Supporting Member
Aug 29, 2016
6,022
W Sacramento, Kalifornia
First, might get vibes, thousand of dollars to fix vibes. Might ask Jerry why he just replaced his driveshaft, I'm sure it was unrelated.
Second, 5.13 will force you to deal with that horrible overdrive everyday. Getting on the freeway your Jeep will be slower than it is now when it shifts out of third gear because your current Jeep can stay in third to much higher speeds. This means your passing power at 60 will be reduced, just simple math.
Third, you can just hit the o/d button and have almost the same final drive without that horrible o/d gap.
Do what makes you happy but don't let anybody sweep the details under the rug. There are big upsides on the trail but there are other things to consider. Read threads, when people like Chris just resort to name calling there might be more to the story.
Care to elaborate?