Re gearing JL sport

Minnesota_JL

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Jeep Wrangler JL sport MANUAL TRANSMISSION
So i have a 2018 JLU sport manual transmission. In the frot i have a Dana M186 and rear Dana M220. I want to re-gear to 4.88. I have about 21,000 miles on the vehicle. Can i use dana 30/44 ring and pinion or do i have to use specific to the m186 and m220? Also should i replace bearings and shims? Or leave as is? And what brand, and install kit should i get?

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So i have a 2018 JLU sport manual transmission. In the frot i have a Dana M186 and rear Dana M220. I want to re-gear to 4.88. I have about 21,000 miles on the vehicle. Can i use dana 30/44 ring and pinion or do i have to use specific to the m186 and m220? Also should i replace bearings and shims? Or leave as is? And what brand, and install kit should i get?

Thanks!
What size tires are you going with? 4.88 with 35s will be pretty low. Probably put your 70 mph cruising rpms up to close to 3k. And yeah do all bearings and seals while youre at it, you will need specific m186/220 gears.
 

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What size tires are you going with? 4.88 with 35s will be pretty low. Probably put your 70 mph cruising rpms up to close to 3k. And yeah do all bearings and seals while youre at it, you will need specific m186/220 gears.
Definitely agree about refreshing all the bearing and seals that come in the master install kits. The 4.88s would be a good match for 35s, we run 37s with our 5.13s, 6 speed and it is perfect. We’re around 2450 at 70. Averaging 16-17 mpg per tank. The standard transmission jeeps are a different animal than autos when it comes to gears. The 8 speed can compensate much better since it has two more gears

Brett
 

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Something to remember even though it’s 35s it probably measures less than that, unless you’re running a true 35. My 37s ridge grapplers actually measure 35.5 ish. I’m thinking I’ll go to 4.88 since I have 8 speed. But still debating, last thing I want to do is be kicking myself for not going low enough.
 
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What size tires are you going with? 4.88 with 35s will be pretty low. Probably put your 70 mph cruising rpms up to close to 3k. And yeah do all bearings and seals while youre at it, you will need specific m186/220 gears.
I have 35in ridge grapplers on right now
 

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Something to remember even though it’s 35s it probably measures less than that, unless you’re running a true 35. My 37s ridge grapplers actually measure 35.5 ish. I’m thinking I’ll go to 4.88 since I have 8 speed. But still debating, last thing I want to do is be kicking myself for not going low enough.
I think that’s a great combo. The 37s and 4.88 on the auto works just right. 5.13s if you have bigger aspirations and don’t do a ton of fast highway or don’t mind poor mileage

Brett
 
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Definitely agree about refreshing all the bearing and seals that come in the master install kits. The 4.88s would be a good match for 35s, we run 37s with our 5.13s, 6 speed and it is perfect. We’re around 2450 at 70. Averaging 16-17 mpg per tank. The standard transmission jeeps are a different animal than autos when it comes to gears. The 8 speed can compensate much better since it has two more gears

Brett
Now can i even run a 4.88 on the front dana m186 and rear m220? The current gearing is 3.45
 

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Now can i even run a 4.88 on the front dana m186 and rear m220? The current gearing is 3.45
Yes. However, this is my personal opinion on the matter, and please take it with a grain of salt. Let’s say 2k for gears and labor. For 3-3500 you can hopefully find some Rubi take out axles. With them, you get then bigger axles (f), lockers f/r and wider front axle. If you install yourself you can save the money on labor. I’m a huge fan of the rubi axle swap but it really depends on your expected uses and budget.

Brett
 
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Yes. However, this is my personal opinion on the matter, and please take it with a grain of salt. Let’s say 2k for gears and labor. For 3-3500 you can hopefully find some Rubi take out axles. With them, you get then bigger axles (f), lockers f/r and wider front axle. If you install yourself you can save the money on labor. I’m a huge fan of the rubi axle swap but it really depends on your expected uses and budget.

Brett
So a better option might be to swap both front and rear? Or just swap the front and re-gear the rear since its already a 220?
 

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So a better option might be to swap both front and rear? Or just swap the front and re-gear the rear since its already a 220?
For the money, that’s my suggestion if you can find the axles. If it was me, I’d do the rear too for the locker but more importantly so the gears match

Brett
 

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So a better option might be to swap both front and rear? Or just swap the front and re-gear the rear since its already a 220?
Why would you want your front axle to be wider than your rear? I would never risk my brand-new Jeep with that kind of incongruency.
 

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Why would you want your front axle to be wider than your rear? I would never risk my brand-new Jeep with that kind of incongruency.
While my OCD could not tolerate it, it won’t hurt anything. Some trucks came from the factory with wider front axles.
 

rustyshakelford

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Why would you want your front axle to be wider than your rear? I would never risk my brand-new Jeep with that kind of incongruency.
While my OCD could not tolerate it, it won’t hurt anything. Some trucks came from the factory with wider front axles.
I misspoke. The f/r are wider on the rubicon. It’s not just the front. Wider is better for stability too.

Brett
 

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