ok so i ordered my 31s and they should be coming soon. i have a manual trans so my gears are the pitiful 3.07. how bad is this going to suck with 31s?? does anyone have any experience? and if i regear im pretty much set on 4.88, do it correct the first time right?! so how would that work? 4.88s and 31s?

hmm wasnt thinking 4.88s dont work with a D35....right?



ahhhhhh this hobby cost sooo much!!!!!!!!!1 :rolleyes: :eek: :)

Find an XJ D44. I sold one for $350, not a bad price. And if you want to do it right the first time, make sure you get ARB's! :D

Edit: 2000 RPM will be about 75 MPH w/ 3.07 gears and 31's
with 4.88's 2000 RPM will be about 48 MPH with 31's :eek:

I had 4.11 and 31's and just the 4.11 gave me high RPMs. It could pull hills in 5th on the highway. I was running about 2800 - 3000 RPM with 4.11 and 33's.

I have 29" and 3.07 in my TJ with the 4.0L and it sucks. I am swapping axles as soon as I get the built (have all the parts just finding out not all the tools) and will be going with 4.56s but I plan to do 32" or 33" soon.

I have seen 4.88 (Superior and Yukon but not Dana) for Dana 30 and 35 but the teeth on the gears are going to be pretty week for those axles.

i really want to get a d44, but i gotta wait till i start workin again. Luckily my commute to school takes about 5 min.

i have a buddy runnin 3.07's and he has 33's he runs between 3rd and 4th gear on the highway but 3rd up hill so your 31's are gonna be to bad for a while

When I first bought my CJ7 it had 3.07 gears with 33" 258engine. The Guy didn't know it had a T5 trans, he thought he only had a 4speed in it. One of the key things I talked the price down on. Most of my driving was done in 4th any hills was done in 3rd sometimes 2nd. when my trans went out 3rd gear was shot. (can imagen why) I installed 4.56 gears lots of power. But now that I'm running 35" The engine seems to be happier. at 60MPH.(my speed days alone passed).

How big of a tire do you want to end up with? Is your Jeep going to stay a daily driver or Just trail rig. Is Fuel mpg a factor?

Here is a link to Randy's ring and Pinion. You can plug in the numbers to see how fast your motor spins

http://www.ringpinion.com/calculators/calcrpm.html

My 2 cents

How big of a tire do you want to end up with? Is your Jeep going to stay a daily driver or Just trail rig. Is Fuel mpg a factor?

Here is a link to Randy's ring and Pinion. You can plug in the numbers to see how fast your motor spins

http://www.ringpinion.com/calculators/calcrpm.html

My 2 cents

well i want to end up with 33s...but that might be a while....a long while, maybe a year or more. its mostly a DD with weekend trails...fuel mpg isnt that huge of a concern as my parents pay(i would try to tell them id save fuel but they have already spent money on me for other stuff.) my daily commute is like...less than 5 miles prob around 2.

my rpms came out to like 1500 at 60mph and its reccemended that it be between 2000-3000

Im running 31's with the dreadful 3.07's, Not bad for cruizing but if a strong head wind, extra people in the jeap or a hill, Its 4th gear, But for now gonna trade to 373 gears as this is also my dd, after the gear change gonna look at 32 or 33's

ok peoples. do you think i can do gears myself?? any special tools? and would i need a new carrier for both axles when going from 3.07 to 4.56??
something to check the backlash...?

I bought a "How-To" video from these people http://www.technicalvideos.com/vide...ferential.phtml It's a great video and shows you all the tools you'll need and how to check everything.I already had dial indicators and stuff.I've got a couple more tools to pick up and I'll tackle 4.10's and ARB install in my CJ.I plan to do more gear swaps inthe future so I don't mind spending the money on the tools.

That didn't work try this one http://technicalvideos.com/videos/differential.phtml

You'll need new carriers. I believe the break is 3.73's. I dont know what you'll need. I've never done gears.

You will need new carriers as Chris said. As far as tools you will need:

Dail Indicator w/ magentic base
Ft/lb torque wrench
in/lb torque wrench
dail calipers - maybe

As far as doing them yourself, I would say maybe. I am doing mine (well I have all the parts and I think all the tools now). From what I have read and been told the key is patenience. Make sure you give yourself plenty of time and do not rush it. If you rush it, you are just inviting trouble.

i personally have not done gears in a jeep but give me a gm 10 bolt and i done a bunches of them paitence is real important, i once thru a set of 4.10's in once in a big hury to make it to the track and broke teeth all the way round the ring after only 3 runs down the track so take your time and you will be fine i soon to be doin it my first time in a jeep real soon

i wanna get a D44 and work on everything out of my jeep, new gears and hopefully a locker of some sort, and then swap it in.

Prices cant be too high to have gears installed if i took the axle out of the jeep and stripped everything off of it...could they?

i wanna get a D44 and work on everything out of my jeep, new gears and hopefully a locker of some sort, and then swap it in.

Prices cant be too high to have gears installed if i took the axle out of the jeep and stripped everything off of it...could they?
It's 150.00 out this way.

It's 150.00 out this way.


ok thats about what i was thinking and gears seem to be between 120ish and 150ish so 300 per axle, 600 for both....aww man i want to do these suckers myself

4.10 gears and 30.5" is what the Rubicon comes with. It runs just fine especially with the 4:1 transfer case. I would not go with a more radical ratio than that, unless you plan to trailer your rig over the highways instead of driving it.

My humble suggestion:

31" - 4.10
33" - 4.56
35" - 4.88

Okay, your 87 XJ sould have on it right now either 195/75R15 or 205/75R15. You want to step up to 31 inch tires and you have 3.07:1 gears.

195's have a diameter of 26.5 inches and 205's have a diameter of 27.1 inches. Most 31 inch tires are not 31 inches in diameter. BFGs are actually 30.7 inches.

Just slapping on the new tires will drop your RPMs by about 300 @ 60 MPH with 3.07 gears when running in your non overdrive transmission gear.

In order to maintain your existing RPMs then you need to step up to 3.55 gears. That is enough of a gear ratio change to justify the gear swap.


G2 = (g1) X (T2) / T1

g1 - current axle ratio
g2 - new axle ratio
T1 - old tire diameter
T2 - new tire diameter

Once you go up in tire size then you will have to compute the speedo gear that you will need as well, just plug the number of teeth on the speedo gear into the equation rather than axle ratios. Have to compute twice if changing both gears and tires at same time.

This info is in alot of different charts as well but don't go by the charts exclusively as not all tire are the same diameter. Brand X tire diameter and Brand Y diameter are not always the same for the same tire size. Close but no cigar.

PM me if I have confused you and you need more info.

Ok thanks for the info jmbrowning and venomized.

When i bought my jeep it had 235s and i stepped up to 31s which measure about 30.5 some of you that have been on the forum as long as i have may remember i have a 2nd jeep(which is a complete beater) it is an 85 with a 4cyl so im fairly certain it has 4.10 gears. what if i wanted to swap entire carriers with gears and all that to my 87 jeep? both are the 30/35 combo. would that work? would i need any special tools? do i have to worry about backlash and whatever else.

Hmmm,
Check your early (rear) axle on the 4cyl. I have run into some NON "C" clip D35's in early Cherokees pre 90 and that would be A HUGE IMPROVEMENT over the "C" clip model axles. If your beater has good axles under it and 4:11's, and then you find it is a NON "C" clip unit, Id swap the whole friggin thing into the good XJ.
'Nuff-said,
Rick

i have a 2nd jeep(which is a complete beater) it is an 85 with a 4cyl so im fairly certain it has 4.10 gears. what if i wanted to swap entire carriers with gears and all that to my 87 jeep? both are the 30/35 combo. would that work? would i need any special tools? do i have to worry about backlash and whatever else.

Even if you swap carriers you'd still have to measure and set backlash. Plus you are not suppose to mix and match ring and pinion gears. So you'd still have to do all the setup.

I would just swap the axles from one vehicle to the other. I do not know enough about XJ if it would be a direct bolt in.

Thats why I say if it's a non C with the 4.11s in the 85, just swap the whole assy.

Thats why I say if it's a non C with the 4.11s in the 85, just swap the whole assy.

I would think that even if it has the clips, make the swap if it will all bolt right in. Sounds like you are set on the 4.11s so swap the entire axles if they fit with or without C-clips.

4.11 gears are not enough to break the axles unless you ae jumping up past 33s and beating on it.

There is a guy on NAGCA with a ZJ running an 8 inch LA lift with 35s and still has the Dana 35 axle and has not had any breakage issues.

im pretty sure both the axles in my 87(which is what i drive) and my 85(the beater) both have non C clip axles. I think that i am just going to swap the entire axles but....im gonna put the brakes from my 87 onto the 85 axles because they are brand new. If my memory is right the brakes should be exactly the same so they will bolt right up? ill have to talk to my dad this weekend to see if we can go pick up my 85 from his dads house(i need my dads jeep, WJ with the v8, to tow the beater) ill try to get the beater this weekend and ill go from there. :) thanks for the ideas peoples! :wave:

i really want to get a d44, but i gotta wait till i start workin again. Luckily my commute to school takes about 5 min.

If you wait and look around you'll find one. I found one with 4.88 and a spool for $500 not bad I think. The guy was using it on an XJ DD.

Brett,
If you have some junkyards around you, hit those up. You might get lucky and find an XJ with a D44.

:D

Brett,
If you have some junkyards around you, hit those up. You might get lucky and find an XJ with a D44.

:D


there are 2 ALL jeep/amc yard around here....unfortunately they are usually aware of what they have and charge some outrageous price. i will keep my eyes out tho

Down here in the High Desert I use www.Recycler.com for alot of good deals. Another source is www.newspaperlinks.com this list the online newspaper in the usa. find some towns around you and look in the want Ads. With the want Ads and recycler you can set up an E-mail alert for key words. Any time somebody places an Ad with your key word you get an e-mail telling you. This gives you first shot at parts. Alot time you will be calling be for it even gets posted. :)

Look around, especially junkyards and government auctions. The ugly pastel green forest service XJ's were equipped with D44 rear axles (but not much else:D).

ahhhhhh!!! i have been extremely dissapointed...my older jeep, 85 4cyl with 5spd doesnt have 4.10s it has 3.73...i counted the pinion and ring gear and divided so im positive thats what it has. and the axles are pretty rusted and crappy so im not wasting my time with that crap. :rolleyes: :mad:

that sucks. 3.73's are better then 3.55's, but not by much. Keep stickin to it. You'll find a D44.

that sucks. 3.73's are better then 3.55's, but not by much. Keep stickin to it. You'll find a D44.


yea i started workin again...found a job refereeing football pays well. so now im keeping my eye out for a D44 and once i get it i will have it benched for a while gettin gears installed and probably some sort of auto locker like an aussie or something. so for now im stuck running 31s with a 5spd and 3.07 gears...it hasnt been to bad so far, i can still sqeal those suckers going from a stop and turning and accelerating. makes me feel like im in a racecar!! lol :rolleyes: