Re-Gearing questions

[Browndog1000]

Didn't want to hijack anyone else's thread.

I have read numerous posts about re-gearing and I still have a few questions I hope y;all can help with.

I have a 2021 High Altitude with the 3.6L V6 and the 8 speed 850RE transmission, 3.73 gears, Teraflex 3.5" lift, Falcon SP2 3.3 Fast adjust shocks, 35" KO2's, after market steal bumpers and winch. I have hardly seen 8th gear since upgrading wheels and tires and have been looking to re-gear to get back to using the full transmission. I have looked at the charts and it seems that 4.56 is the sweet spot. I do go off-roading but don't have any desire to do any gnarly rock crawling. Would it make sense to upgrade to 4.56 gears or would I be better suited to jump up to 4.88's? What are the pros and cons of going going with 4.88's over 4.56's? I don't plan on going to larger tires, but that could change when the 35's need to be replaced. I am not too concerned about gas mileage but I would like to get decent mileage again if possible. Thanks for taking the time to read and respond.

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[c20040215]

In my opinion, 4.88 would work great with 35" (slightly on the aggressive side) and still be okay for 37".

 

[JT1]

Jeep thinks 4.56s are perfect with small 35's and the 8 speed (XR). BUT if you ever think you will tow, or go to a bigger 35 or a 37, go 4.88.

 

[Some Random Guy]

4.56 gives you larger pinion. Since you aren’t starting from 4.10 you’ll still notice the improvement.
4.88 is better able to handle a bigger tire if you change your mind later.
With the auto, FOMO isn’t so bad if you go 1 size too small.
I’d recommend 4.56 based on what you said.

 

[Jeep’n Jay]

I initially went 4.56 with 35's and that worked ok. I didn't really have any complaints and seemed to work on and off road. When I went to 37's I was going to go 4.88 but when I got to the shop I ended up putting in 5.13's and am REALLY glad I did. 5.13 in my opinion is perfect for 37's. So using that logic, I would go 4.88 for 35's if it were me.

Gas mileage since the install of 5.13 last May (11 months ago) I have overall averaged 18.1 mpg and I offroad ALOT. 70% offroad crawling and 30% highway. 3.6 motor.

 

[landshark99]

You will notice a big improvement going to 4.56 gears, but if there is a chance you will go to 37s I would do 4.88s just in case so you only do it once

 

[word302]

Jeep thinks 4.56s are perfect with small 35's and the 8 speed (XR). BUT if you ever think you will tow, or go to a bigger 35 or a 37, go 4.88.

By that logic Jeep thinks 3.45s are perfect for 32” tires and a manual transmission.?

 

[JT1]

By that logic Jeep thinks 3.45s are perfect for 32” tires and a manual transmission.?

if he had a manual, I would have told him to get the 4.88s for 35s.

 

[DrJ]

I just put 4.88s in mine with 37” STT Pros… I see 8th on occasion, but kinda wish I’d done 5.13s. In your case I’d go with 4.88 as they will still work well with 35s or with a small 37 (like the KO2) if you go that route in the future.

Kind of funny side note: I took my Jeep in to get the gears done in January. They completed the rear diff, but when they opened the front it had copious metal shavings… some kind of failure of the e-locker. They put the cover back on and pulled the front drive shaft then had me take it to the dealer… three months later I finally just got the front axle replaced (yes, they replaced the entire axle) and I’m going in for the front gears this week. Haha! I must be the only 2WD JLR on the road! Btw, I have 5000 miles on my 2021.

 

[Browndog1000]

Thank you to everyone for the advice, 4.88's it is. Will be getting them done in June.

 

[CarbonSteel]

4.88 and 35's with the non-etorque 3.6L will be a great experience. When I was in Texas with that setup, it was nice and torquey, had plenty of power, and staying in OD gears was a non-issue.

You will be very happy with it and if you ever go to 37's it will lose some of the torque, but at sea level, it will still be very "usable".

 

[scottijohn63]

I initially went 4.56 with 35's and that worked ok. I didn't really have any complaints and seemed to work on and off road. When I went to 37's I was going to go 4.88 but when I got to the shop I ended up putting in 5.13's and am REALLY glad I did. 5.13 in my opinion is perfect for 37's. So using that logic, I would go 4.88 for 35's if it were me.

Gas mileage since the install of 5.13 last May (11 months ago) I have overall averaged 18.1 mpg and I offroad ALOT. 70% offroad crawling and 30% highway. 3.6 motor.

When I went to 35's and a 2.5 Mopar Lift I went with 4.88's, and am extremely happy with this combo. Lots of performance! Very fun to drive!

 

[Steph1]

Just regeared to 4.56 after putting on 35s and can testify that it is worth every penny. And I hate to break it to you, but you have 3.45 gearing, not 3.73

 

[Browndog1000]

Just regeared to 4.56 after putting on 35s and can testify that it is worth every penny. And I hate to break it to you, but you have 3.45 gearing, not 3.73

I have the High Altitude, it comes standard with 3.73. After I swap gears, if I find they put 3.45's in there Jeep will have some splainin to do in the way of cutting me a check!!!

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