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For those going with 37s, are you regearing??

4xFUN

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I have a 3.6 auto and recently (have about 1200 miles on the 4.88's) went with a UD44 w/4.88's and geared the rear to mach obviously, running 37x12.50 KO2 D's on Mopar 8.5x17 wheels, 29PSI cold. My 2 cents (this based on a 2-door Rubi) for what's its worth is 4.88's are MORE than enough and if doing it again running either 35" or 37" KO2's, I would probably go with 4.56's.
4.88's are probably ideal with an even heavier 4-door running larger/heaver 37" tire-wheel combos...
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RDender

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I re-geared with 35's and am definitely glad I did especially since I am now running 37's. I do not understand those who say 4.10's are "just fine" with 35's and 37's. Speaking from experience, if putting it in gear and it moving means it is "just fine", then OK, but there is no comparison between 4.10's and 4.88's with a 3.6L and an 8 speed.

Mine would not hold 8th and sometimes not even 7th, constantly up and down shifted, and MPG suffered. That is all history after the re-gear.

YMMV!
How did it do with the 4.88 ‘s when still on the 35’s?
 

CarbonSteel

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How did it do with the 4.88 ‘s when still on the 35’s?
Very peppy--it was night and day from 4.10's and 35's.

I just wished I would have gone 5.13 now that I have 37's as I lost some of the torque.
 

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How did it do with the 4.88 ‘s when still on the 35’s?
Yes with 37s 488 puts it back to stock some people say 513 but you can look at YouTube videos Eddie that has the way of life YouTube channel. He's been on their 5 years now. He showed the comparison 513s you lose the down gear when you need to kick in to pass 488 is perfect if you want stock or want it back to stock I kept my four cans I didn't want to waste the money on it right now. Every now and then if mine doesn't hit eighth gear I'll use the manual and then it has like a memory my buddy the dealership was telling me it has like a memory it'll do it again when I have to hit a gear on its own and then it doesn't have any problems for a while so mine's fine I don't everybody can say it's not the same it may not be exactly like 488 would put it back to stock but if I'm hitting 7th and 8th gear I'm fine I'm not towing so I don't care. I don't need to spend 1700 right now I'm okay with it like I said most time it hits 7th and 8th and holds it
 

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4.88 for automatics
5.13 for manuals

Bite the bullet.............. Build your rigs correctly!
 

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I am now running 37 KM3s with 4.88 gears, I did have 35 KM3s with the 4.10s, after the 35s I would not want to run 37s with the 4.10s. With the 35s and 4.10s, I found long steep grades to be slower than with stock 33s, also the lack of 8th most of the time, offroad I find the 4.88s with the 37s to be a much better setup, with the previous setup mileage was between 14.5 to 17 if I was lucky, now with the 37s on 4.88 I am between 18 and 20.5
 

CarbonSteel

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Yes with 37s 488 puts it back to stock some people say 513 but you can look at YouTube videos Eddie that has the way of life YouTube channel. He's been on their 5 years now. He showed the comparison 513s you lose the down gear when you need to kick in to pass 488 is perfect if you want stock or want it back to stock I kept my four cans I didn't want to waste the money on it right now. Every now and then if mine doesn't hit eighth gear I'll use the manual and then it has like a memory my buddy the dealership was telling me it has like a memory it'll do it again when I have to hit a gear on its own and then it doesn't have any problems for a while so mine's fine I don't everybody can say it's not the same it may not be exactly like 488 would put it back to stock but if I'm hitting 7th and 8th gear I'm fine I'm not towing so I don't care. I don't need to spend 1700 right now I'm okay with it like I said most time it hits 7th and 8th and holds it
???

Are you saying those who are running 37's and 5.13's are not able to downshift to pass?
 

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I put 37" Ridge Grapplers on my new JLU XR with 4.56 gearing. I am happy with it. Runs in eighth gear most of the time on the highway. Drops into seventh when going uphill. I usually do.not drive over 70 MPH though.
 

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???

Are you saying those who are running 37's and 5.13's are not able to downshift to pass?
Of course not I'm not saying you can't answer I'm saying you can feel the difference it doesn't down shift one lower gear I'm trying to remember the video if you go to way of life on YouTube Eddie he's been doing videos for like I said five six years on all those bills everyone knows who he is he did one on that subject and show the difference and talked about it I'm not an expert on it I'm just telling you what he said but of course you can downshift but there's a difference
 

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???

Are you saying those who are running 37's and 5.13's are not able to downshift to pass?
. Here watch the video you should know who he is he's been around a long time and knows a lot about Jeep's and wheeled all over the country and! I guarantee more than you and me. This guy is very smart you can watch the video halfway through he talks about with 513 it won't go down into fourth gear for the passing gear with 488 it will. Trust me this guy knows what he's talking about you can watch all those videos he's been doing this for a long time
 

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Jammer

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. Here watch the video you should know who he is he's been around a long time and knows a lot about Jeep's and wheeled all over the country and! I guarantee more than you and me. This guy is very smart you can watch the video halfway through he talks about with 513 it won't go down into fourth gear for the passing gear with 488 it will. Trust me this guy knows what he's talking about you can watch all those videos he's been doing this for a long time
After you watch the video let me know what you think. surely you know this who this guy is he's been making YouTube videos for a long time. he's not just some fly by night guy. He only has like nine Jeeps he has one of the original trucks when they were first made and he's got a badass JK his gladiator got the long wheelbase on it with 42 I think it 40s. Just looking at some of his recent videos of his build's and he knows what he's talking about I love his garage you'll see all the Jeeps he has in there it's crazy
 

Jammer

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. Here is another really good video. surely you know who Brad is with trail recon is. They go over landing everywhere all over the country and down in Mexico Baja. I know you know who he is I hope you do here's a good video on his brand new Rubicon he talks about the difference in what he went with between 488 and 5:13. It's a good video for people that don't understand the gears. They show them open and what the difference is some people have no idea what they even look like. It's a very good video. Would love to hear your opinion on the two videos
 

CarbonSteel

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. Here watch the video you should know who he is he's been around a long time and knows a lot about Jeep's and wheeled all over the country and! I guarantee more than you and me. This guy is very smart you can watch the video halfway through he talks about with 513 it won't go down into fourth gear for the passing gear with 488 it will. Trust me this guy knows what he's talking about you can watch all those videos he's been doing this for a long time
I ran 4.88 with 35" tires before I upgraded to 37" (which should be close to 5.13 with 37's) and had ZERO trouble downshifting to pass. With that said, I would question when (at highway speeds) you would ever need to downshift all the way to 4th to pass someone. I have seen 5th a time or two at speeds above 60, but never fourth so even if what he is saying is correct, that would seem to be a non-issue--at least for me.

We also have to bear in mind the difference in gearing (with the same everything else) between 4.88 and 5.13 is about 5%. Do you actually think that a 5% lower gear is going to cause a vehicle to perform the way he states? Color me skeptical at best.
 

rlong69

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5.13's on 37's with 6 spd manual and LOVE it. 4.88's are the MINIMUM I would ever throw gear money at to run on 37's. I drive 75-80 mph 5 days a week to work in it too. Just last week when not paying attention went 87 mph for a bit. Love this setup. Power back and crawl speeds are amazing. It is a 24 valve V6, yes it turns some higher RPM's now, who cares. It has a freaking 6500 rpm redline. I have zero experience with the turbo-4 this is my second JL with the V6 and NO electro boost crap.
 

CarbonSteel

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5.13's on 37's with 6 spd manual and LOVE it. 4.88's are the MINIMUM I would ever throw gear money at to run on 37's. I drive 75-80 mph 5 days a week to work in it too. Just last week when not paying attention went 87 mph for a bit. Love this setup. Power back and crawl speeds are amazing. It is a 24 valve V6, yes it turns some higher RPM's now, who cares. It has a freaking 6500 rpm redline. I have zero experience with the turbo-4 this is my second JL with the V6 and NO electro boost crap.
^^^ this all day^^^

I am kicking myself for not installing 5.13's--especially after moving from sea level to almost 7K feet. For me, I am waiting to see if Jeep comes out with the 3.0TT in 2023 before deciding what to do next...
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