Would re-gearing provide better acceleration?

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Torpedo01

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I have a ‘98 Sahara with the 4.0, 32” Cooper Stt Pro tires, 3 speed auto, and 3.73 gears. On flat level ground and when cruising at speed, everything’s all good, no real complaints.

But when leaving my neighborhood, there’s a long, gradual hill with highway traffic coming from both directions. Even with it floored, man, I can’t seem to get up to speed fast enough.

I’m wondering if regearing would noticeably improve the situation so I don’t have to fear for my life daily, or if that’s just what life is supposed to be like with a TJ.
 
Given that you have the 3-speed auto, 3.73 or 4.10 would both be ideal for a 32" tire.

I don't think it's your gears, you're just dealing with the nature of the 4.0 and the piss poor aerodynamics of a Jeep Wrangler. They aren't going to be fast by any means, in fact they are quite slow.

Welcome to life with a TJ :LOL:
 
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A 32RH with 32” tires and 3.73 gearing shouldn’t feel that Terrible. Even on a slight uphill. The TJ isn’t going to win any races, but isn’t necessarily a slouch with the 4.0 either. To answer your question though, yes, regearing will help, but isn’t totally necessary in your case
 
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Chris said:
I don't think it's your gears, you're just dealing with the nature of the 4.0 and the piss poor aerodynamics of a Jeep Wrangler. They aren't going to be fast by any means, in fact they are quite slow.
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Compared to what, exactly? In it's time, the 4.0 was considered quite powerful and fast compared to the competition.
 
Jerry Bransford said:
Regearing both axles to 4.10 would significantly help its performance and acceleration. No, 4.10 would not create excessive highway rpms. 😊
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Hi, Jerry!
I have a question for you. I will get rid of those terrible 3.07 gears in a couple of months & I’m torn between 4.56 & 4.10 gears. I know that most folks here swear by 4.56 (my tires are 33/12.50 BFG KO2s) but the Jeep will make the occasional 800 mile highway round trip to visit family.
Your thoughts, please. Thanks.
 
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I had 33s, 3speed auto, 3.73s for many years and never had a complaint with acceleration. We don’t have North Carolina hills here though.

You could temporarily swap on some smaller wheels and tires to get a comparison feel of what it would be like with lower gears. Should be able to calculate what the equivalent gear ratio would be. See if it makes you happier with the acceleration.
 
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I have an 06 4.0 6 speed and I can say that with 32's I'm happy with the gearing, but I wouldn't be happy with a 33" tire on. My speedo is almost perfect with this combo too.
If you are going with a 33" then move to a deeper gear than 4.10. Otherwise you'll be constantly downshifting, or not using 6th at all.
 
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Mudflat said:
Hi, Jerry!
I have a question for you. I will get rid of those terrible 3.07 gears in a couple of months & I’m torn between 4.56 & 4.10 gears. I know that most folks here swear by 4.56 (my tires are 33/12.50 BFG KO2s) but the Jeep will make the occasional 800 mile highway round trip to visit family.
Your thoughts, please. Thanks.
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Your transmission is the 6-speed so yep either of those would work. Your part of Texas is pretty darned flat so 4.10 would be fine if most of your driving and offroading is on your surrounding flat terrain. Personally, living in SoCal (cough cough) I'd go 4.56 even with the 6-speed just because my TJ regularly sees some hills and mountains.
 
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Jerry Bransford said:
Your transmission is the 6-speed so yep either of those would work. Your part of Texas is pretty darned flat so 4.10 would be fine if most of your driving and offroading is on your surrounding flat terrain. Personally, living in SoCal (cough cough) I'd go 4.56 even with the 6-speed just because my TJ regularly sees some hills and mountains.
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Thanks for the quick reply, Jerry. We will do some wheeling in the Texas hill country &, since we are RVers, the occasional trip to the Rocky Mountains isn’t out of the question.
 
Thanks for the feedback guys - as far as weight reduction, I have a softtop that I mostly leave down, no doors, stock bumpers, removed the back seat...there’s really not much else I can do to shave off more pounds at the moment.

Think I’ll try 4.10 gears and see if that helps any, although I do plan on going to 33’s when my tires wear out...
 
Mudflat said:
Thanks for the quick reply, Jerry. We will do some wheeling in the Texas hill country &, since we are RVers, the occasional trip to the Rocky Mountains isn’t out of the question.
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Based on that I'd take the conservative route and go with 4.56. 'Tis better to be slightly overgeared than slightly undergeared.
 
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Jerry Bransford said:
Regearing both axles to 4.10 would significantly help its performance and acceleration. No, 4.10 would not create excessive highway rpms. 😊
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I agree. Regear to 4:10 and go slap a JK owner and tell them that's from a guy named Jerry Bransford.

Let us know what happens.
 
Running 4.10s and a 6 speed myself, if I were to regear for 33s it wouldn't be to 4.10. I think you would be always on the edge of happy, but not quite there. Acceleration will be improved with 4.56s and you will have that extra pep to not feel the need to rev up so high to upshift.
I live in upstate NY so there isn't a lot of steep climbs here, but mostly longer stretches of hills and on 32s I'm just to this side of happy with my 4.10s. If I didn't have them installed because of being a Rubicon then I definitely would have gone to a deeper gearing.
 
Chris said:
Given that you have the 3-speed auto, 3.73 or 4.10 would both be ideal for a 32" tire.

I don't think it's your gears, you're just dealing with the nature of the 4.0 and the piss poor aerodynamics of a Jeep Wrangler. They aren't going to be fast by any means, in fact they are quite slow.

Welcome to life with a TJ!
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Torpedo01 said:
Hah! It sure does feel that way sometimes, was even looking into a 4.6 stroker for the day when the 4.0 dies.

Can’t imagine how the 2.5l’s can even get these things moving.
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Hard to make a brick aerodynamic hahah. Stokers are sweet! Agreed on the 4 cylinder, can't imagine one on bigger tires.
 
Torpedo01 said:
Pulled the trigger on the 4.10 regear and also front & rear Truetracs while they have it opened up since there was no additional charge for labor. Hope that’s enough to conquer this unavoidable incline into traffic when leaving my house.
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That will really wake up your Jeep! 💪
 
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