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How bad is it? 4.2 5 speed with the pageout trans and 3.55 gears. If i do regear should i go 4:56? Its a daily and i will always want it to be able to drive long distance on the highways, wheel for a weekend, and drive home. 4.10’s? 4.56? Dont fine a lot of threads for the 4.2
 

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4:10 is the best for 33s.
 
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I'd suggest 4.56 if you're gonna regear... I have 4.10's and 33's on my 4.0 yj and while it works decent, I wouldn't want to give up any hp on the highway...

The only reason I could see for you choosing 4.10 over 4.56 is if you get a great deal on axles w 4.10 already in em like from a 4 cyl 5 speed
 

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I had 4.56 with a 4.2l and 35's, 33's and 31's at one point or another on my wrangler. It was geared way to low for the 33's and 31's and okay with the 35's. 4.10's would have been better since you've probably noticed the 4.2l has great get up but none past say 50mph. A 4.0l is a different beast where you would gain better hp at highway speeds but the 4.2l will fall on its face due to having a lower RPM torque and HP curve.
 

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How bad is it? 4.2 5 speed with the pageout trans and 3.55 gears. If i do regear should i go 4:56? Its a daily and i will always want it to be able to drive long distance on the highways, wheel for a weekend, and drive home. 4.10’s? 4.56? Dont fine a lot of threads for the 4.2
Let me share with you my experience. I had a 2.5 inch TF lift kit with 305x70x17 bfg km2's and initially had the 4.10 gears that the Rubicon came with. For the stock tire, the 4.10 were a beast!!! When I upgraded, I could tell that my higher gears were slow and had an issue going uphill. After re-gearing to 4.88s, my jeep drives much better on the highway and uphill. Much smoother throughout each gear now. The 4.10's would work, but what size exactly? The 305's I have are not much smaller than 35's hence why I went with the 4.88's. I am going to a 315 or 35 (whichever is cheaper) this Friday and 4.88 is perfect for this size in my opinion. 4.56 would probably work really well if you are planning on staying with 33's. In fact, that's the way I would go.
 

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C5Wagner,

I just aquired a similar setup to yours it seesm. Friday I purchased a 1993 with a 5.7 L31 an 4l60E trans from a 1998 surburban. Also an NP231 TC. It has 4.56 and 33 in tires.

Anyway, I see you recomend 4.10s with 33s but from your tag line it looks like you are running 4.56. Why the difference? I am feeling like the 4.56 may be a bit low, or perhpas I have a driveline issue that needs to be sorted out. The jeep just doesn't move anywhere near like the old chevy trucks did with the 5.7. I feel like it is reving quickly but not transfering that energy into forward movement. Do you feel your setup works well with the v8? I am also wondering if I might have a torque converter that isn't locking up all the way.
 

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C5Wagner,

I just aquired a similar setup to yours it seesm. Friday I purchased a 1993 with a 5.7 L31 an 4l60E trans from a 1998 surburban. Also an NP231 TC. It has 4.56 and 33 in tires.

Anyway, I see you recomend 4.10s with 33s but from your tag line it looks like you are running 4.56. Why the difference? I am feeling like the 4.56 may be a bit low, or perhpas I have a driveline issue that needs to be sorted out. The jeep just doesn't move anywhere near like the old chevy trucks did with the 5.7. I feel like it is reving quickly but not transfering that energy into forward movement. Do you feel your setup works well with the v8? I am also wondering if I might have a torque converter that isn't locking up all the way.
Welcome to the Forum.
 

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C5Wagner,

I just aquired a similar setup to yours it seesm. Friday I purchased a 1993 with a 5.7 L31 an 4l60E trans from a 1998 surburban. Also an NP231 TC. It has 4.56 and 33 in tires.

Anyway, I see you recomend 4.10s with 33s but from your tag line it looks like you are running 4.56. Why the difference? I am feeling like the 4.56 may be a bit low, or perhpas I have a driveline issue that needs to be sorted out. The jeep just doesn't move anywhere near like the old chevy trucks did with the 5.7. I feel like it is reving quickly but not transfering that energy into forward movement. Do you feel your setup works well with the v8? I am also wondering if I might have a torque converter that isn't locking up all the way.
My comment above reflects when I had a 4.2l motor, ax15 manual, and 33's. With the 4.2l and 33's, I recommend 4.10.

As for my current V8 setup, I can easily smoke the tires with 4.56 and 33's. I think it is a perfect combo. When I go up to 35's, I'll probably go 4.88 or 5.13 depending on when I get the axles I want.

To test your torque converter check this link: Road runner converters and maybe you need to test the transmission line pressure, a tranny shop can do that for you if you don't know what that is or have the gauge as your pump may not be delivering enough pressure. Early in my build, I had a problem with lack of power too with the v8 at first until I found out it was a fueling issue: My fuel issue
 

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Interesting, I can't even begin to smoke the tires. I was just trying to figure out if I have a setup problem or a mechanical problem. I belive your trans is just an earlier version of the 4l60e so first gear is probably similar. mine is 3.1 to 1. it is feeling like a transimssion issue. I got what I consider a smoking deal so I figured I'd work it out. 9K for a super clean body, clean engine swap, 4 inch supension lift, and 2 inch body lift I belive (I need to dial that back. I am too old and fat for that kind of height), brand new 33s rear locker, recent paint including a paint job of the frame and all driveline parts. hard top, etc. Only real issue is the performace is off and the gagues don't work. oh and the seat foam is worn out. nothing major.

I am a fairly competant mechanic, and my brother is a professional mechanic, I'll get after the transmission but probably not untill after christmas.
 

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Instead of guessing use a gear ratio calculator Gear Ratio Calculator

Enter stock specs on one side of the calculator, then enter the specs of your Jeep as it is now on the other side. Play with gear ratios to bring the RPMs and road speed as close to stock specs as you can get, then you may consider going one step lower.
 

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Discussion Starter #11
The 4.2 is a torque monster and I personally love it. Blah blah “the carter bbd sucks” shut up. Take care of it. Ive owned it for almost 4 years now and having my first car hav a carb has made me learn so much

As for gearing i was thinking getting axles with 4:10 already in them would be the cheapest (dana 30 and ford8.8) in the meantime how nad would 33’s on 3.55 be? 5th gear even useable? Right now i can hit 70 easy and 80 if its a long enough flat section of highway
 

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5th? You'll be lucky to use 4th lol
 

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I’m not sure about that calculator. It says my Jeep can do 188mph at 6k rpm in 5th gear. Bonnieville here I come. Going to set a new record for a stock YJ. Lol
 

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I’m not sure about that calculator. It says my Jeep can do 188mph at 6k rpm in 5th gear. Bonnieville here I come. Going to set a new record for a stock YJ. Lol
Ok, get that 4.0 up to 6200 without blowing it up and HANG ON... LoL
 

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4.2 4:10's on 31's 2000rpm 60mph, 2500rpm just around 74mph with passing power, 2750rpm 80 on flat starting to top out on torque, 2900rpm downhill/flat at 85 or call it a day.

The 33's I originally bought it with got traded down when 65mph was all it had without constant downshifting to get the speed back up.

Now a 4.0 … That's a game changer
 

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AWWW.. C'mon guys, trying to illustrate the 4.2 limitations, not start OP thinking about motors....:)
 
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I’d rather have a Hemi. Lol
Me too, just way cheaper and easier to install a chevy engine in a jeep. Also, every dodge transmission that would fit in a wrangler sucks except for the old TF727.
 

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Discussion Starter #20
4.2 4:10's on 31's 2000rpm 60mph, 2500rpm just around 74mph with passing power, 2750rpm 80 on flat starting to top out on torque, 2900rpm downhill/flat at 85 or call it a day.

The 33's I originally bought it with got traded down when 65mph was all it had without constant downshifting to get the speed back up.

Now a 4.0 … That's a game changer
So 4.56 is what youre saying
 
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