4.56 vs 4.10 (d30/8.25) 97XJ

Unless I missed something in my searches, I was looking for a discussion on these two gearings for a 97XJ auto with d30/8.25 axles. But here's my scenario, I don't drive the Jeep as much offroad as I want to, I'd say about 20% of the time. The rest is spent on the highway, etc. So I am looking for the best gearing ratio for what I need. Right now I am running 31's TrXus Mud Radials (which are a little bigger than 31's by the way) with the stock 3.55 gearing.

I have heard that 4.56 is too low for what I would be using and I have heard that 4.56 is perfect. And just recently someone told me that the 4.10 gearing would be just right, etc.

For locking purposes, I plan on putting in a limited slip in the rear and front or a powertrax in the rear and no-slip in the front. Like I said, I only use this about 20% of the time offroad but when I do go offroad I would like some better traction, etc which is why the limited slip was suggested to me by several people.

So at this point, just looking for some comments, ideas, feedback and possibly the best place to get the gears, limited slips/powertrax/no-slips.

Thanks,

Chris

From what I have read on the forum, the limited slip won't be much different than an open diff offroad. I do not have first hand experience though. I think they'll wear out pretty quick too.

If motor is stock (and a 4.0) I say 4.10's are your ticket to happy highway driving and offroad fun.

fwiw

tetsulo

I'm running 4.10's and will be putting in a Powertrax No-Slip in the next week to ten days. Tire size is 32x11.50x15, AW4, 4.0L. this is also a DD and I took it off-road for the first time yesterday. I was very pleased with the performance of the gears and even more impressed with how well it handled the trail overall.

4.56 and be done.

TrXus measure large and my 33x12.50 BFGs that I use for the street measure small so they are probably actually pretty close in rolling diameter. I have 4.88s and it's perfect. 4.88s arent' available for your 8.25, so get the 4.56.

oh yeah, and get a real locker. with an auto tranny it is nearly invisible on the street. ARB or Detroit would be best, Aussie (is it available for 8.25?) or No Slip would be good too.

you'll kick yourself if you ever plan to really wheel it if you get the 4.10's. I'd say get the 4.88's but they are not an option to you. So 4.56's is the only way to go. As Brett said, get a real lock, I am not a big fan of ARB's in the rear (too much money, not enough function) so i'd say a detroit where i'd put my money.

The debate over 4.10-4.56-4.88 will live forever, but I'll toss in my two bits

I dunno how hilly it is around Cinci, but if so... consider the 4.56:1. Especially if you don't have a long interstate commute, or do a lot of long road-trips. I had to run awhile with 31" TSL radials on my 4.0/AW4 with 4.56:1 (my DD is 50 mi of 2 lane, rolling hills @ +400' sea level) I thought it was fun, with no penalty at the gas pump. If I had 4.56:1 (or 4.10) in my current DD on P225, It would be even more fun, but with probably a MPG and a D35 penalty.

There is a broad range of overlap with what tire/gear combo will make the owner happiest. (depending on their use, predicted tire sizes, loads etc...) Gearing a bit lower than stock suits me, particularly with older/hi-mile 4.0l/AW4s, that see little interstate travel. Off road, lower gearing just makes it smoother.

no aussie for the 8.25 yet, talking to a rep and he told me its doubtful if there will be due to whats already on the market.

are you planning on going to a bigger tire size or pulling a trailer? if so 4.56 will give the better performance, if just staying under 33" get the 4.10s for all around fuel and offroad. about the locker, if saving some money for awhile is your skill, save and get an ARB(s). selectable for others that might drive your heep, while on the trail, snow,etc. lived in Cini (off cin-day road in liberty township) would have been nice to be able to not slide around so much with the locrite. just dont have a place/time/axle choices around me to swap so im building the 8.25 (29 sp, arb, shock relocation, etc.) and its been good so far.

-jpx3

get 4.56s, anyone that says otherwise is a moron

4.56's and a Detroit get my vote

jpx3 said:

no aussie for the 8.25 yet, talking to a rep and he told me its doubtful if there will be due to whats already on the market.

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They list one on their web site for the 27 spline 8.25, but not the 29.

guess I'm a moron.

80% dd means the vehicle should be optimized for the road not off road in my opinion.

still just my .02 though

tetsulo

At this moment, meaning the next 2-3 years I wouldn't go any higher than 33's (in fact I may go to 33's in the next couple months before the gear install), so even with that in mind and knowing again that this is used 80% of the time it is driven on the highway and around town 4.10's would be the right choice? What would 4.56's give me that 4.10's wouldn't for my situation?

Also, all that is available for the back (8.25) that I know of is arb, detroit, and no-slip. The front (d30) all I know of is arb, detroit, ez, OZ, loc-rite, and limited slip. Knowing that money is somewhat of a concern and that I only wheel it 20% of time, what do you all suggest? I want something I can wheel with when I get a chance but something that won't suck on the open road if that makes sense.

I am playing stupid on this, but someone said that an open diff would be the same as a limited slip...why?

And last question is...do I need a locker on both the front and rear at the same time. I realize that if I am going to put in gears and have everything open I might as do it, but let's say I can't...should I just put them in the rear?

Thanks,

Chris

tetsulo said:

guess I'm a moron.

80% dd means the vehicle should be optimized for the road not off road in my opinion.

still just my .02 though

tetsulo

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that you are
even if it was 95/5 i would still get 4.56s. it is still very road friendly. do your 2 cents come from experience or just speculation, if the latter shut up until you know what your talking about, if the former forgive me for my rudeness

chris i have a no slip in my 8.25 and it works great, for the price of it you cant go wrong. after reading about the warranty problems and the commoness of breaking the locker when popping a shaft i'm not sure if i would get a detroit. sure a limited slip is better than open, but if you want to do any serious offroading i would just get a locker.HTH dont need both, i would lock the front first if you are just gonna do one. without starting a discusion here just look for the other thread about it on the first couple pages. with a lunchbox locker like aussie lock right and no slip it will be easy to add them later on if you want

tetsulo said:

guess I'm a moron.

80% dd means the vehicle should be optimized for the road not off road in my opinion.

still just my .02 though

tetsulo

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How is gearing the vehicle to suit the guy's tastes NOT optimizing it for the road... w/o knowing how this guy loads out his Jeep during the 80% and the 20%?

Think about it, for a good running 4.0l with either trans, 30-35" and 4.10:1-4.56:1 is an acceptable range. The 4.0l's torque curve is wide enough to deal with it. At 3000 rpm in 3d/4th gear (1:1), 31" with 4.56:1 is around 60 mph, 31" with 4.10 is around 67... Stand on it, upshift, or back out of it. :dunno:

I have 4.10's and 31" tires. I think it is a perfect combination for road and off-road. Any bigger tires than that I would not even think of getting lower (numerically) than 4.56's. I would have gotten 4.56's with my 31's anyway if the 4.10's weren't practically free to me.
If you are thinking of ever going to a taller tire, whether it be now or several years from now, listen to the experienced here, do it once, do 4.56's.

Hey...no problem guys. Your right about the load between the 80/20, we don't know. Woody says the range between 4.10 and 4.56 is acceptable for 31's. Which is consistent from what I have read from the forums. So different opinions regarding gearing from one side of the 'acceptable' range to the other doesn't seem to make anyone a moron in my book.

matt

Even at 100% DD use, you'll be happier in the long run with the deeper gears. While using my 93 4.0 AW4 as a DD I didn't have to deal with the kind of hills that exist around Cincinnati. You WILL appeciate the lower gears. Period. Anyone who tries to convince you that you'll pay a penalty in gas mileage has neither any experience on the subject nor any idea how his vehicle operates.
I love my 4.88s and 33s and would go deeper if possible. When (not if) I lose the D30 in favor of something beefier, I'll be dipping into either 5.13s or 5.38s. Once you've driven a rig with effectively lower than stock gearing, you will never be satisfied with less.

A spool is cheap, but for no more than you get offroad it doesn't seem like your best option. I run ARBs front and rear now, but have run a No-Slip in the rear when I still had the 8.25. You can't beat a selectable locker like the ARB for versatility, but they come at a higher price and require on-board air or some other engagement mechanism (cable, wiring, tinfoil hat, etc.). After a selectable, the next best option in my opinion given the way you describe your useage is a toss up between a No-Slip and a spool. It doesn't sound like you require the strength advantage of a full case locker like the Detroit. I think you'd better appreciate the smoothness of the drop-in No-Slip's synchronizers. After a couple of weeks for break-in, I never heard from mine again unless I intentionally got on it in a parking lot. It would lock and unlock very smoothly and seemlessly. That said, an auto locker, even a really smooth one like the No-Slip, is not as predictable in the slippery white stuff as a spool. A spool is generally inappropriate for the street and will lead to much quicker tire wear in the rear - a tradeoff for the cheaper purchase cost. But you know exactly how it is going to behave in every situation - like a one-piece solid axle. Driving either an auto locker or a spool on the street, epecially in the winter, is a matter of learning and getting used to the particular quirks. Neither is insurmountable and those who speak in superlatives and absolutes on the subject are simply spreading bogus information.
How do I know? Here's a clue: it WASN'T from reading it on the internet or hearing it from some old-timer at the shop.
Enjoy.

Okay, so far I'm looking at 4.56's especially if I am going to go to 33's anytime soon...makes sense.

Now for the lockers, the back I am looking at a no-slip after reading "What Rd" and "Ramseys" replies, but for the front (d30) I was looking at my options and what I have narrowed it down to are; No-slip, lock-rite, and EZ locker.

So now I have two more questions. First, what is an EZ locker exactly and is it a good option for me and my front and two, out the options above for the front, which one is recommended for what I will be using the Jeep for? I know that the guys recommend the no-slip for the back, but what about the front?

You guys have been a big help, thanks.

Chris

lock right for hte front. i have riden in a jeep with a lock right in the back and it was loud and not near as quiet and smooth as my no slip. i got the rear no slip for that reason. up front i have a lock right where it is ok since it wont have those same manners since in 2wd it doesnt have power. all you will get is some ratcheting from it in sharp turns. no need to extra cash on a no slip up front IMO. i have had the lock right up front nearly a year and it has been working great, i would get it again( and the no slip in the back) if i had to do it again.