djlarroc

Anyone running/ran this combo?

Getting ready to buy parts. Would like the extra torque from the 4:56, but not sure if it's too deep for 31" tires. Don't really plan on going bigger than 32" in the future. I'm thinking mpg may even be better than if I went w/4:10.

Gorillaxj

I would think its to deep, would have high RPM's at free way speeds. if youw here going to jump to 33's I would say go for it!

You can use this calculator to decide for your self.

honestly with 31-32's I don't think re-gearing is worth the money. If you want to go 4.10's then I would try and find a axle set with them already in the, to keep cost down. just my .02

c0ncEpT

When it comes to gearing always go a step deeper than whats considered "standard" IMO. That is if you plan on wheeling at least.

If everyone says use 4.10's use 4.56's.

I DD my Jeep to the tune of 10K miles a year. Although it doesn't see a lot of highway time.

I had 32's on my Jeep when I 1st go it and it wasn't to bad on the street(11-12mpg). Although I am locked front and rear the thing was an absolute dog offroad. 4HI felt almost worthless.

I have 35's and 4.88 and I wish 5.13 was an option. If my Jeep ever gets axles they will have either 5.13's or 5.38's in them.

If your wheeling it I say absolutely go for it. If it sees 95% pavement the cost isn't worth the return if your only running 31's.

djlarroc

Well it will be a mostly camping/wheeling rig so most of the use will be for off-road, and dd if my main dd breaks down. Guessing probably about 3-5k miles per year.

I agree w/you guys that for 31s, re-gearing probably isn't even a good idea. I don't plan on going bigger, but I do want to lock the rig front & rear so that is why I'm thinking of doing the re-gear too. I know the carrier break for D30 is 3:73+ so might as well.

And so since I'm going to re-gear, should I do 4:10s or 4:56 is what I can't decide. My last xj, I went the cheap route and did 4:10s and it was an absolute dog! but that was on 34" tires. My mileage was bad too.. about 180-200 miles per tank. I started to hate driving it, but was not about to spend to re-gear it again, so I ended up selling it.

Don't want to make that mistake again. I'm sure 4:10s will be much better on 31s, but the extra torque would be nice.

Gee oh Dee

FROM PERSONAL EXPERIENCE.....

4.10s and 31s on a manual trans is stupid. Maybe with an auto its a bit better.

My 4.10s and 31" combo make first gear absolutely useless for on road driving.

I now have a 4 speed trans, I start in 2nd.

33s would be a nice tire, but 32s would prolly hit a sweet spot.

Jarrett

If it were mine i'd go ahead and get 4.56's. Chances are if it's your camping/wheeling rig you're gonna want to go bigger than a 31 someday. JMO though.

Donnie_K

transmission is a factor here too... 4.10's on a 5 speed are about the same as 4.56's on an automatic.

Metmknice

For those that say gearing for 31's is a waste. I totally disagree. I went 31's because they were a good price used on CL. It was a dog on the road with the 3.55's. Off-road was alright.
I got a deal from a friend on a C8.25 geared with 4.10s (definitely an upgrade from a Turdy5). And also got a deal on a newer front axle/gears. Haven't geared the front yet, but with the 4.10's I can make it up grades keeping a steady speed. I still down shift sometimes, but do not have to have my foot all the way in it.

IF you can find a 4cyl/manual XJ it will have 4.10s in it. That really is the cheapest way, and bolt-in.

I got my mileage back, and even improved (except for now using winter fuel), but still better than with 3.55's.

If you have a manual, going to 3.55's or 3.73's would do fine, but I would still recommend minimum 4.10's

Rock Toy

The difference between the automatics .75 OD ratio and the manuals .79 ratio doesn't make any kind of relevant difference on the highway, and the manuals 3.83 ratio first gear may not be good with low gears on the street but makes it great for trails.

Rpms at 65 mph with an auto and a manual.

65x4.56x336x.75/32 = 2334 rpm at 65 with the AW4
65x4.56x336x.79/32 = 2459 rpm at 65 with the AX15

That is only a difference of 125 rpm at 65 mph. Going with 4.10 gears with an AX15 would be a difference of 124 rpm lower rpm than the AW4 with 4.56 gears, or 2210 rpms at 65 mph.

Gee oh Dee

So you don't think its bad that my 1st gear is completely useless?

Rock Toy

If you use your Cherokee as a DD and rarely use it on trails, yes, your first gear would be useless, but I on the other hand rarely use mine as a DD.
I trail ride with my Cherokee a couple of times a week and with 4.88 gears and a 3.83 first gear in my transmission and only a 2.72 transfer case, I would really like to have the cash to install an Atlas 3.8 to 1 transfer case, lower gears in my case are better.

Gee oh Dee

You posted just before I did. Sorry, not really aimed toward you. Lol

However, I DD mine, and wheel as much as I can. The low first gear is nice, but I also have 4 low for when I really want to crawl.

MUDRUNNER AZ

To the OP i dont see if you have auto or not but i would think so and with OD your xj can handle the 4.56's pretty well. Keep in mind what kind of weight you will be carrying also, gear,bumpers spare parts/tire, coolers and what ever else we stuff into them.

*Jonathan

I have 31's and 4.56s with the AW4. I love it and drive my jeep 45 miles to work on the highway. At 70 I'm reving about 2500-2600 (right in the powerband of the 4.0). Best of all.. I'm ready to throw some 33's on whenever I get a good deal. Do it right the first time if you are going to regear and skip 4.10's altogether if you ever think you'll go bigger than 31's

MUDRUNNER AZ

Quote from concept post #3: "I have 35's and 4.88 and I wish 5.13 was an option. If my Jeep ever gets axles they will have either 5.13's or 5.38's in them".

I ran 35's and 4.88's for years and it was good. went to 36's a year or so ago and only that inch had an effect on things kinda wierd. now i run 5.38's and love it on the hi way as well as off road.