4.10 or 4.56 gears for 4.0L/5sp with 33s?

I have a 94 5sp with the 4.0L which is about to go under the knife and get ARB lockers, Rubicon 4.5" lift, SYE and 33x12.5x15s. I know that I'll have to change the gearing and I'm debating between 4.10s and 4.56s. (Right now it has the stock 3.07s)

My thought goes like this:

I don't plan on running anything larger than 33s since I drive to off-road events versus trailering... and plenty of times I've gone over 2K miles round trip to go to an event... Therefore I don't think I'll appreciate the ride with 35s...

I've always enjoyed the relative power and acceleration of the XJ when it was stock and therefore I don't want to go to an overly slow and/or sluggish setup.

Therefore I think that I can get away with 4.10s and that would help the budget since I'm planning on swapping the rear Dana 35c for a Ford 8.8 which already comes with (1) 4.10s and (2) disc brakes...

However, there's a little voice inside of me saying that I should pop in the 4.56s just in case I ever decide to go to 35s... but then I go back to thinking of what trip from California to Texas, and back, would feel like running on 35s and I go back to my, "33s is all I'm going to get" mantra...

Thoughts, opinions?

I have your exact set up with 4.10s. I would rather have 4.56. I find myself in 4th gear if I drop below 60. For me 4.56 is the way to go.

BA

I have that problem right now in 5th gear if I drop below 70... Freeway driving in town is always a choice between lugging in 5th or revving a bit high in 4th...

I ran 4.10s with 33x12.50 MT/Rs for a few months (including a trip to Moab) then upgraded to 4.56s.

No debate. 4.56.

Currently my rig is a 1996 4.0/5spd with 33x12.5 MT, 4.5 Rubicon lift and I have the 4.56 gears and I love them. I think the gearing is perfect on dirt or pavement - plenty of power and torque. Gas mileage isn't bad either I average 13-14 around town and about 18 highway. I agree with the others go with the 4.56.

Before you spend the money on re-gearing with 4.56's, think hard about your desire for 35's. In my opinion, 4.56's are too high for 35's--the same difference between running 33's with 4.10's vs 4.56's. My experience with 4.10's and 33's, is that you drop too far down in the 4.0l's torque range on the highway--either lugging in 5th or over revving in 4th. 33's and 4.56's were better, but still not enough poop when loaded with camping stuff and trying to climb a decent grade. I solved the problem by swapping in a 5.7L for the 4.0L. Now the 4.56's and 33's are just right. The main reason I don't go to 35's is that I don't want to spend the money for the lower gears I think are necessary to be happy with the 35's on the highway.

xjbubba said:

I solved the problem by swapping in a 5.7L for the 4.0L.

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Unfortunately I can't really do that, unless I'm willing to also change the transmission, since I have a manual tranny... I've been thinking about a turbo kit if I find that the extra weight of tires, suspension, skids, etc is too much for the existing engine.

I don't know about you guys, but the word "stroker" has had my interest ever since I got my Jeep.

Didn't mean to imply all is lost unless you swap out the 4.o for a V8. Just that if you think you'll be going to '35's, you won't be happy with 4.56's, so think ahead. As you know the cost of re-gearing is not trivial. But also think about what else going to 35's may require: bigger front and rear axles, as a starter. By the way, you said lockers were your next step. You didn't say which axles you currently have. I believe 33's and lockers will stress a D30/D35 combo beyond what I would want to live with, even with the 4.0, which has a fair amount of low end torque. Just food for thought.

do the 4.56s. if you go to 35s you wont be so unhappy as if you went 4.10s.

cterlizzi said:

Thoughts, opinions?

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Go here and do the necessary maths. Not to be a smartarse, but it should help.

33's, long trips and a stick..... 4.88's without a doubt. I"m happy with speeds up to 80mph (and going more then that in a lifted XJ is nuts... heck, going 80mph is pushing it!). I'm pretty happy on the trail and when I'm not hauling all my extra tools/parts and other crap I get 17~18mpg.
I drove it out with this setup to the Con once, drove it out to Moab twice and I would not hesitate to do it again same way if I had to build it again. 4.10's are about right for 31's (had that setup for a while). It's an all around great combo: perfect for the highway, pretty decent on the trail (although while in 4L you will be dreaming of a 4:1).
When I moved to the 4.88's I had them on with 31's for one trip to the Con. It was AMAZING! Now while I couldn't top 70mph without shooting the RPM's through the roof, the trail capability was AMAZING. Soon after I got 33's and the highway speeds came back to normal range (I could push it up to 80). Anyways, the response on the trail was great, the capability was really great (although again I dream of a 4:1 too damn often). In any case if you have the choice, upgrade your rear axle to D44 or 8.8 and go 4.56's all the way around and if you're not planning to go above 33's you will not regret it. Your jeep will have the perfect balance of highway/trail capability.

casm said:

Go here and do the necessary maths. Not to be a smartarse, but it should help.

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Calculators be damned. According to it, if I went with straight out calculations when going from 29" tires to 31's from 3.07's I should be happy with 3.28's. Ok so why is it that with 4.10's I felt right at home with great fuel economy and great highway speed? I cringe at the though of having 3.55's (which would have been way better then the suggested 3.28's!). Anyways, IMHO the manual transmission models were undergeared from the factory and they suffered with 235's and stock gears (I know, I had that setup and I couldn't climb out of the LA basin without cussing the stock gearing!!!).
In any case, the calculators do not take into account:
1. increased weight of tires/new rims (latter might not be an issue)
2. increased weight of the vehicle to accomodate more suspension crap and whatever else you bolt on
3. increased air drag due to lifted suspension.

I have 4.10s and 33s with a stroker and I think its about right around town as its stupid fast But once I get on the highway and am doing 75-80mph I feel like I am really revin the crap out of the beast. Going that fast doesnt feel horrably bad in my XJ, its just the RPM seem a little high at 3k which is when I wish I had 3.73 or 35s with the stroked motor. It didnt feel as bad or seem that high with the 4.0L, 33s, and 4.10s. If you are planning on 35s later and want a very reliable trail rig and DD you should ditch the Dana 30 and swap in a Dana 44 and at that point regear to match the 35s but thats just my opinion.

AARON

MrShoeBoy said:

I have 4.10s and 33s with a stroker and I think its about right around town as its stupid fast But once I get on the highway and am doing 75-80mph I feel like I am really revin the crap out of the beast. Going that fast doesnt feel horrably bad in my XJ, its just the RPM seem a little high at 3k which is when I wish I had 3.73 or 35s with the stroked motor. It didnt feel as bad or seem that high with the 4.0L, 33s, and 4.10s. If you are planning on 35s later and want a very reliable trail rig and DD you should ditch the Dana 30 and swap in a Dana 44 and at that point regear to match the 35s but thats just my opinion.

AARON

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stroker = oranges
stock 4.0 = apples
get the picture?

Kejtar said:

Calculators be damned.

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Fair point, but I never said to put absolute faith in them; at best, the gearing calculators give an ideal number based on limited criteria. If anyone takes them as gospel (rather than as a guideline), that's extremely short-sighted on their behalf.

4.56s no doubt. I have 33s and an auto wit h4.56s and I'd love 4.88s. I drive 80 miles a day too.

I am planning 33 and have been working on the same problem. by my calculations


33" tires & 4.56 gears will return my jeep to nearly (within 5%) of the stock 27" tires and 3.55 gears.


I will be going 4.56

stop asking these damn questions. 4.56s!

I have a buddy that runs 33's, a 5spd and 4:88's and couldn't be happier. Gas mileage may suffer a little on the highway but you may see a small increase in town. I run 4:88' on 35's and wish I could have gone deeper but I'm limited by my D30. If you ever plan on going to a larger tire I would suggest the 4:88's and save yourself a headache later.

Neil