Gears&sye

[Dirt Dogg Rydas]

I need to add gears to my XJ, but not sure what to use. I have 31" mt's but want to switch to 33". I've been recommended 4:10's for the 31's but will it be good enough for the 33's or should i just go with 4:56? Also I have a 4.5" lift from rough country. I was told the SYE was not needed but recommended. How can I decide wether to add it or not? I'm trying to stay low budget since Im not working right now.

[COSXJFAN]

For 33s, 4.56s will be closest to stock. As far as the SYE, you can use your experiences with your Jeep to figure that out. Are your getting vibrations with your current set up? Are you planning on going higher down the road? A SYE is going to be stronger than stock, and will eliminate some of the vibes, if you're having them. I'm at 6.5"s + and don't have one. I had my DS lengthened by 1" and the wall thickness increased, and I have had no issues with this set up. I also have 4.88s with 33" tires, but I did that knowing that I'd be going up to 35s one my next tires purchase. With the 33s, on the highway I'm at about 2600 RPMs at 65 MPH, which to me, is fine, this is your call. HTH!!

[cher96]

I need to add gears to my XJ, but not sure what to use. I have 31" mt's but want to switch to 33". I've been recommended 4:10's for the 31's but will it be good enough for the 33's or should i just go with 4:56? Also I have a 4.5" lift from rough country. I was told the SYE was not needed but recommended. How can I decide wether to add it or not? I'm trying to stay low budget since Im not working right now.

I believe with those ratios the person was thinking about trail riding and power. There is a balance between Economy and Power. With 32s my XJ does fine. I am more on the Economy side since I live in the city and drive it every day. I have no troubles on the trails with 3.55 gears. When I go to 33s, I will regear to 4.11s and change out the Carrier in the Dana 30. If I remember right, I think 4.88 is as high as you could go with a Dana 30 because of the size of the Ring Gear.

You could go with the 4.56s for 33s for a balance for both Highway and Trail Blazing. A lot of Off Road people I know go with that. Trail only Rigs, around here, that run with a Dana 30 usually go with the 4.88s.

AS for the SYE... I run at 5"s of lift with no SYE. My suggestion would be: Install your Lift and if you have any Vibration at all... get a SYE.

Hope this helps.

[Mudderoy]

rings and pinions for d30 and c8.25 with master rebuild kits and a d30 carrier cost me $507 with shipping.

I have heard that having the gears swapped is as low as $350 an axle and as high as $500.

It will have the least impact but I'd do the SYE. If I had to do it over again I would have done the SYE first before everything else.

I would not go with 4.10 gears. If I'm going to go to the HUGE expense of regearing I'm going to do 4.56 (of course that is what I did). Once the gears are in you can easily adjust the gearing with the diameter of the tire.

As it is I can go to 35" tires and my gearing will still be good.

[Voldemort]

Well I am just going to put in 4.88 right off so I can upgrade if I want it will only help and you do not want to do it more than once or your wallet will be hurting. As for the SYE if you are getting bad vibes from the rear at highway speeds or at all then you want to look in to one,But I say try the Hack-n-tap it is alot cheaper and easy to do.http://www.ironrockoffroad.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=IROR&Product_Code=IR-X_HNT
http://www.go.jeep-xj.info/HowtoSYEconversion.htm

[cher96]

Disclaimer: I forgot that when I posted that I do fine with 32" Tires and 3.55 Gears that I have Heavily Modified my XJ and more than likely I have much more Torque and Horsepower than a Stock XJ.

X2 on the H&T from IronRockOffRoad. I have that setup but have not installed it because I haven't any vibration at all.

[Dirt Dogg Rydas]

All I get is a little wiggle at the steering wheel not realy a whole lot that didn't happen before the lift though, now for the gears would there be any problems if I were to get the 4:56's and still run 31'' tires

[Mudderoy]

All I get is a little wiggle at the steering wheel not realy a whole lot that didn't happen before the lift though, now for the gears would there be any problems if I were to get the 4:56's and still run 31'' tires

How fast do you drive on the highway?

If you keep it down around 60 or 65 mph I think you would be ok. It's just a gas mileage thing.

[DETOURS]

4:10's anything under 35's, unless it's mostly a trail rig.

What type of wheeling do you do?
How often?
Is it your dailey driver?
Lockers? Do you have or plan on lockers?

[Dirt Dogg Rydas]

4:10's anything under 35's, unless it's mostly a trail rig.

What type of wheeling do you do?
How often?
Is it your dailey driver?
Lockers? Do you have or plan on lockers?

I mostly use it offroad since I have two other cars but I need it to be driveable on the road in case one of the other breaks down so I usually only use it in the weekend and if I offroad far i put it on the tow dolly. lockers will be down the road

[Voldemort]

I do not want to get anyone's hopes up cause to find this is like getting a pic of Bigfoot .But, there is a Tranny Yoke from a GM Th350 I think from a '68-'82 truck that has 27 spline and are very cheap (If you can find one). It will match up perfectly to the TC so all you would need is a Front Drive shaft and Whop there it is. Here is a pic.
http://i23.photobucket.com/albums/b364/Dave41079/jeep/SYE/SYE001.jpg
http://i23.photobucket.com/albums/b364/Dave41079/jeep/SYE/SYE002.jpg

[cher96]

Wow, what a fantastic tip!!! :thumbsup:

Too bad I paid $99+ for mine. :sad0147:

[COSXJFAN]

4:10's anything under 35's, unless it's mostly a trail rig.

What type of wheeling do you do?
How often?
Is it your dailey driver?
Lockers? Do you have or plan on lockers?

4.88s and 33s, and I love it. It drives great on the highway. It's no speed demon, but come on it's a bread box on wheels, how fast do you need to go!! LOL!!!

[BuckB91XJ]

Here are the gears that will give you the best combo of power and fuel economy for a given tire size:

3.55:1 (or your stock gears) - up to 30s
4.10:1 - 31 thru 32
4.56:1 - 33s (34s if you get those odd sized LTBs)
4.88:1 - 35 thru 36
5.13:1 - 37 thru 39

I've never personally known anybody who runs larger than 39s on an XJ on the road....and he never does highway speed.....and he has a Ford 9" rear and D44 front. He just puts around town. He says it is scarey doing anything over 40 MPH. He trailors it everywher else. I also wouldn't recommend stock axles, even re-geared for any tires larger than 35s

[Mudderoy]

I do not want to get anyone's hopes up cause to find this is like getting a pic of Bigfoot .But, there is a Tranny Yoke from a GM Th350 I think from a '68-'82 truck that has 27 spline and are very cheap (If you can find one). It will match up perfectly to the TC so all you would need is a Front Drive shaft and Whop there it is. Here is a pic.


Don't you have to drill a hole in this part then drill and tap the shaft on the transfer case so you can bolt this on the shaft? I can't remember if you have to actually cut the shaft down by several inches as well.

[cher96]

Yep, your right. There is a little more to it though.

[Mudderoy]

Here is the write up on NAXJA (http://www.naxja.org/forum/showthread.php?t=959008&highlight=th350)

[Voldemort]

Don't you have to drill a hole in this part then drill and tap the shaft on the transfer case so you can bolt this on the shaft? I can't remember if you have to actually cut the shaft down by several inches as well.

OH YEA! No matter what you have to hack-n-tap I was just letting you know that there is a yoke out there that can be found in a JY (Junk Yard) for cheap along with the front drive shaft so you could get the parts for less than $50 bucks:eek:if you can find it. Sorry I didn't mean to confuse anyone.:sign0013:

[Mudderoy]

OH YEA! No matter what you have to hack-n-tap I was just letting you know that there is a yoke out there that can be found in a JY (Junk Yard) for cheap along with the front drive shaft so you could get the parts for less than $50 bucks:eek:if you can find it. Sorry I didn't mean to confuse anyone.:sign0013:

No problem, I confuse people all the time. I was trying to remember what I had read. It dawned on me where I read it after my post.

[DETOURS]

I mostly use it offroad since I have two other cars but I need it to be driveable on the road in case one of the other breaks down so I usually only use it in the weekend and if I offroad far i put it on the tow dolly. lockers will be down the road

I'd consider stepping it up then, rock or mud? standard or auto?

[DETOURS]

4.88s and 33s, and I love it. It drives great on the highway. It's no speed demon, but come on it's a bread box on wheels, how fast do you need to go!! LOL!!!


Automatic, 33's & 4.88's.......I'd say your in overdrive on the street alot of the time...great take-off, but little top end, excellent for the trail though.

[mizedog]

Automatic, 33's & 4.88's.......I'd say your in overdrive on the street alot of the time...great take-off, but little top end, excellent for the trail though.


I hope you're right Spanky. I just took mine to Crazy Ed's to have 4.56s stuffed in mine. I was very tempted to go with 4.88s, but need to drive from CO to CA to visit the Mother-in-law. I hope the 4.56s will get me what I need in the mountains and still let me drive on the highway over distances. Too late now.

My CJ had 4.56s and 35s and was fine with the V8's torque. I kind of wished for 4.88s when doing the big rocks. The XJ won't be doing Sledgehammer like the CJ, and will jump from 32s to 33s probably in 2010 or 2011. 35s probably won't happen on this Jeep.

I guess in the end I could put a 4:1 in...:thumbsup:

[2000XJ]

I'd say that 4.56's is a great gear set for an XJ. With 4.56's you can comfortably drive and wheel with 33's or 35's, and it doesn't shrink the pinion gear as much as 4.88's will, so they're a tad bit stronger.

As for the SYE, there are various options out there that are good. You can do it for cheap or you can spend alot of money on it. It's really up to you.

[DETOURS]

I hope you're right Spanky. I just took mine to Crazy Ed's to have 4.56s stuffed in mine. I was very tempted to go with 4.88s, but need to drive from CO to CA to visit the Mother-in-law. I hope the 4.56s will get me what I need in the mountains and still let me drive on the highway over distances. Too late now.

My CJ had 4.56s and 35s and was fine with the V8's torque. I kind of wished for 4.88s when doing the big rocks. The XJ won't be doing Sledgehammer like the CJ, and will jump from 32s to 33s probably in 2010 or 2011. 35s probably won't happen on this Jeep.

I guess in the end I could put a 4:1 in...:thumbsup:

You're in good shape.

This tall gear stuff all came about from crawling.......rock crawling.
As a reminder, the taller you go.....the smaller the pinion......the smaller the pinion.....the less heat it can take before it fails at highway speeds.

Please dont believe eveything you read.
:headshake:

[COSXJFAN]

Rock crawling is the majority of what I do. You're right, I do as little hwy driving as possible, but when I'm on the hwy it does fine. I wouldn't want to drive across country in it, for more reasons than the gearing alone!! I put the 4.88s in knowing that the next tires I buy will be 35s as well.:thumbsup:

[mizedog]

Well, I got the Jeep back on Saturday and have driven it around town a little. I've been gentle on it even through Ed said not to worry about it. I can tell that it handles the 45mph hill MUCH better. It still may go into 3rd, but I barely have to touch the gas. I can tell the engine and tranny are working a lot less now. I've had it up to approximately 65mph and it was at about 2,220 rpm. It's louder at that speed than it was. I'll probably keep it at or below 70 on my trip to California in two weeks.

So, part of me would have like 4.88s, but with the 32s, I'm ok with my choice.