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3.8L 6spd with 33 gears

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Old 05-10-2014, 07:22 PM
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Default 3.8L 6spd with 33 gears

Hello all,

I have searched and read numerous threads on gears. I currently have 33's on my jeep, don't ever really plan on going up any, maybe to 34's, and I have 3.21 and the 6 speed with the 3.8. I can get around ok now if I don't use 6th gear. My question is I want to do a gear change as my next mod, but don't know what I would go with. I'm stuck between 4.10's and 4.56's. I know a lot of people say don't waste your time or money with 4.10's, but I do a lot of highway driving to work as my JK is my DD. My question is does anyone have a 6 speed with the 3.8 and 4.56 gears? Is 2700 rpm at 70 mph too much? I would like to keep some of my MPG. Since I do a lot of highway driving I keep leaning too 4.10's. Any thoughts? I have attached the rpm charts. Thanks!


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Old 05-10-2014, 07:47 PM
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How wide and heavy are the 33s? I ran KM2 255/80-17s (33x10.5) for a couple of years on 4:10s and no problems on/off road, mountains etc, but if yours are heavier acceleration may be affected a little and wider may show up at speed up a steep grade due to extra wind resistance, but probably not noticeable. I would do the 4:10s, but the 4:56s will feel peppier.
Old 05-11-2014, 04:34 AM
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I am running 295/70/17 nitto trail grapplers. I'll have to look up weights on my wheels and tire combo.


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Old 05-11-2014, 04:59 AM
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Originally Posted by silverjk2011
I am running 295/70/17 nitto trail grapplers. I'll have to look up weights on my wheels and tire combo.

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I have 285/75-17s now and have to drop to 5th on some hills on the road.
Old 05-11-2014, 06:01 AM
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I still have 4.10´s with my 37x13.50 Toyo´s. Personally doesn't bother me. I can still gain speed uphill on the highway. I can do 95 mph no problem if I need. Granted I don't get there fast or anything but it doesn't take all day to get there either if I want.

Personally I think you'll be fine with either. However, I wouldn't spend all that money to put in 4.10 gears. I'd go with 4.88 so you have more umph and can go up in tire size if you ever wanted to without hesitation.

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Old 05-11-2014, 10:27 AM
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Not sure where you're located, but I will be installing my fully built 44's into my '07 next week. I have my Dana 30/44 stockers up for sale. 4.10 gears, limited slip out back. I've been on 35's for the last 6 months and it drove fine on the highway at 55 in 6th. My '10 has 3.73 gears and 35's, and you can definitely tell the difference. 6th gear only happens on the interstate, above 75. Looking to sell the pair for $1000. They are straight, and have never been in the rocks. Upgraded because I'll be going to 37's soon. Let me know if you're interested! They are located in Fort Worth, TX.
Old 05-11-2014, 12:21 PM
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Originally Posted by D3ADLY
I still have 4.10´s with my 37x13.50 Toyo´s. Personally doesn't bother me. I can still gain speed uphill on the highway. I can do 95 mph no problem if I need. Granted I don't get there fast or anything but it doesn't take all day to get there either if I want.

Personally I think you'll be fine with either. However, I wouldn't spend all that money to put in 4.10 gears. I'd go with 4.88 so you have more umph and can go up in tire size if you ever wanted to without hesitation.

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4.88's and 33's with a 6 speed? Sounds like overkill to me.


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Old 05-11-2014, 12:22 PM
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Originally Posted by jsukey
Not sure where you're located, but I will be installing my fully built 44's into my '07 next week. I have my Dana 30/44 stockers up for sale. 4.10 gears, limited slip out back. I've been on 35's for the last 6 months and it drove fine on the highway at 55 in 6th. My '10 has 3.73 gears and 35's, and you can definitely tell the difference. 6th gear only happens on the interstate, above 75. Looking to sell the pair for $1000. They are straight, and have never been in the rocks. Upgraded because I'll be going to 37's soon. Let me know if you're interested! They are located in Fort Worth, TX.

I'm in east TN, that's tempting, but don't know if I could do it now or not. How many miles on the axles?


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Old 05-11-2014, 12:33 PM
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Just over 100,000. No leaks, or gear noise though. They run great. Complete except for ABS sensors. But you can simply reuse yours though.
Old 05-11-2014, 01:24 PM
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Originally Posted by jsukey
Just over 100,000. No leaks, or gear noise though. They run great. Complete except for ABS sensors. But you can simply reuse yours though.
How about you yank out the gears and send them to me haha


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