Need more gearing

5spd with 4.88's in the diffs and 35's.

I love this setup for daily driving, moderate trails, and snow. However, the gearing blows when it comes to rocks. There's no finesse, and it's a pedal dance the entire way. I need more gearing.

I figure I have four options, each with their pro's and con's.

1. Teraflex Tera Low 4:1 w/2Low
2. 231 to 300 doubler
4. Swap in a different t-case (241, 300, Atlas)
4. Give in and just swap in an auto.

What do you guys recommend? What are you running, or have had good results with?

I really don't want to shell out the money for a new t-case (Atlas, Stak, 241). This isn't a comp rig (digs aren't really needed), just a daily driver/weekend warrior.

I'm worried that if I swap in a 4:1, that it will be too slow for the mild trails. Has anyone experienced this? Is there a speed limit or rev limit on the Tera Low's?

I really like the idea of a 231 to 300 doubler (more gear selection), but it would be a lot of work (still a daily driver). It would also require significant floor cutting, and new drive lines.

I could always just swap in an auto. It would probably be cheapest, but I enjoy the 5spd for daily driving. I get decent mileage (17-20), and it really pays off on descents.

What do I do?

TJ 4:1 Rubicon swap. Its awesome, and easy.

~James

The 4:1 swap does have its pros and cons, and I think that it really sucks on an auto, but that's because I like the speed in 4-Low. Since you have a standard, the 4:1 swap might be your best option since you control which gear you're in. If you think it's too slow for the mild trails, just shift gears I don't have any experience with the other options you have, so hopefully someone else will chime in.

stumpXJ said:

TJ 4:1 Rubicon swap. Its awesome, and easy.

~James

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I've thought about a 241 swap. However, it seems like a new case, new yokes, and a 2Low kit would be pretty close to the price of an Atlas. :dunno:

jeeperguy21 said:

The 4:1 swap does have its pros and cons, and I think that it really sucks on an auto, but that's because I like the speed in 4-Low. Since you have a standard, the 4:1 swap might be your best option since you control which gear you're in. If you think it's too slow for the mild trails, just shift gears I don't have any experience with the other options you have, so hopefully someone else will chime in.

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Is there a speed limit or rev limit on the Tera Low's? I've read about possible overheating issues.

Also, how's the noise?

I've been wheeling for a looonnnnggg time. I ran manuals up until about 6 years ago and swore by them. I got tired of snapping axles with the stroker and converted to an auto. Wheeling is so much easier and less tiring. I did add the 1-2 and torque converter lockup switches and love it. The biggest disadvantage was compression braking going down long downhill runs, but the switch setup fixed that.

^^^I'm with the Old Man on this one. I use to swear by a manual shift in my CJ's and after I bought my first XJ that had a auto and then wheeled it, there is no comparison. I would swap in the auto.

i have noticed that people who swear by standards have never ran an auto offroad.

people who swear by autos have run both offroad.

anyway, i run 5.38's with 35's and love it on the street,highway,offroad, everywhere.

i like to keep my floor somewhat intact so the doubler/big case ideas arent really an option. i bet i could squeeze some setups under there though, but havent cared enough to look into it.

There is also a kluneV /Dana 20 option that will fit, but not many people have them.

I had a stick in my CJ, love the auto in the XJ for everything except mud, the 1-2 shift sucked, and it wasn't as easy to rock back and forth. I've since added the AW4 controller and have better compression braking to boot.

I am running a 5 speed - taking out Atlas/Stak as options, I think I would rank the rest like this from a purely gearing standpoint:
1 - doubler (with one being 2.72, the other 4:1).
2 - switch to auto
3 - Tera low

That is not taking into account the cost and work involved with the doubler. I am running the Atlas 4 speed (I took the easy but expensive way out ) and the gearing selection is nothing short of spectacular. Autos with stock low range and 4.88's do very very well offroad, and that kind of reduction is no longer needed with the torque converter there. Lastly, the Tera low would help a lot with rocks, but is kind of a band aid, as it only fixes one issue, whereas the others are more diverse. Something to think about. Tera suggests you stay out of 5th gear to keep from burning up the planetaries. If you were to get them, I would switch to high range any time you want to go faster than 3rd gear in low range.

You didn't say which front axle you are running. If its a D-30 then I wouldn't waste the money on a Stak or a Atlas, you loose the "front dig" feature anyway, the D-30 will not hold up. If you have gone bigger in the front then those options would move up the list for me. For the trails/rock we run here on the east coast my D-30/Longfields combo is working great with 35's since I have plenty of ground clearance at the diff I rarely hang up hard enough to have throttle hard to get out. Its all relative so to speak.

TORX said:

Is there a speed limit or rev limit on the Tera Low's? I've read about possible overheating issues.

Also, how's the noise?

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Yes there is a max RPM for the Tera-low(I think its 4000).Ive got the Tera-low in my 2000 and the NV241OR in my 95,the Tera is definately louder.

xjtrailrider said:

You didn't say which front axle you are running. If its a D-30 then I wouldn't waste the money on a Stak or a Atlas, you loose the "front dig" feature anyway, the D-30 will not hold up. If you have gone bigger in the front then those options would move up the list for me. For the trails/rock we run here on the east coast my D-30/Longfields combo is working great with 35's since I have plenty of ground clearance at the diff I rarely hang up hard enough to have throttle hard to get out. Its all relative so to speak.

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D30 for now. I'm far from a lead foot, and I think the added control of more gearing will help it survive that much longer. I agree that I don't really need the dig feature. I'm just wanting some crawling capability.

Also after more thought I just realized I have a 21 spline 231. I have a BA10 (If it's not broke why fix it?) so the 21 spline comes along with it unfortunately. I don't really want to build something off that platform, because I foresee myself swapping it over to a new XJ eventually. So I guess I could either swap in an AX15 and then go 4:1 or doubler, or just swap in an AW4.

Decisions, decisions...

RCP Phx said:

Yes there is a max RPM for the Tera-low(I think its 4000).Ive got the Tera-low in my 2000 and the NV241OR in my 95,the Tera is definately louder.

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I rarely peak 2500 so there's no worries there.

Which do you like better? Are they mated to an auto or manual?

TORX said:

Which do you like better? Are they mated to an auto or manual?

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Both are auto's,I love both my rigs for different reasons!

If you go with the Tera 4 to 1 you'll like it, and it will be the simplest option for you. It won't be too low. I had a 4 to 1 in my XJ with an auto, 5.13's, running both 35's and then 37's, and it's not too low. If you figure out the ratios, at least on my automatic, you'll be close to dropping a gear in each of your current gears......basically loosing OD and picking up a lower 1st gear. So, if you like a little speed in low range, you'll be very close to having like you are right now in 4th, if you get what I mean. I seriously doubt you spend that much time wound out in low range overdrive, it's just not a big deal.

Also, while I like wheeling with an automatic, low gears with a stick still work pretty well. If you like a stick, I wouldn't change to an auto with stock T-case gears over getting a 4 to 1 with the stick. The doubler would be a sweet setup, with even lower gears, but it's a lot of work. Good choice if you have the time and energy for it, if not you'd be happy with the 4 to 1. Also, too much low gearing won't be good for the D30.

I have a automatic with a 4:1, 4.88s and 35s. 95% of the time, I love the gearing. The other 5% of the time it is either to low, or to high.


I do not have much experience wheeling in a manual, but I have driven my friends Toyota with a pretty low crawl ratio (150ish:1 I think), and I stalled it on pretty much every obstical. Maybe thats because I dont know how to drive a manual on the rocks, or because Im just a bad driver. All I know is I love my automatic, and feel like Im in a lot more control then any of my friends with manuals.



The 4:1 is loud. Much louder then stock. I dont have much of an interior left, and there is a definite gear drone at almost all speeds. I think the max rpm for them is somewhere around 3k rpms, but a quick visit to their site will tell you that.


I ended up going with a used 4:1 with 2low because I got one heck of a good deal on it. It was also nice because it was a bolt in affair. Not having to redo driveshafts, shifter linkage, or floor modifications were big advantages.



I have a couple friends who have just finished 231/300 doublers, and I am really considering doing one. I would love to have more choices for gearing, but at the same time, I feel like I would worry to much about what gear I am in, if I need to be lower, or higher, etc. The lower gearing would be awesome, even with an automatic, although I think it might be approaching the realm of to low.

Goatman said:

If you go with the Tera 4 to 1 you'll like it, and it will be the simplest option for you. It won't be too low. I had a 4 to 1 in my XJ with an auto, 5.13's, running both 35's and then 37's, and it's not too low. If you figure out the ratios, at least on my automatic, you'll be close to dropping a gear in each of your current gears......basically loosing OD and picking up a lower 1st gear. So, if you like a little speed in low range, you'll be very close to having like you are right now in 4th, if you get what I mean. I seriously doubt you spend that much time wound out in low range overdrive, it's just not a big deal.

Also, while I like wheeling with an automatic, low gears with a stick still work pretty well. If you like a stick, I wouldn't change to an auto with stock T-case gears over getting a 4 to 1 with the stick. The doubler would be a sweet setup, with even lower gears, but it's a lot of work. Good choice if you have the time and energy for it, if not you'd be happy with the 4 to 1. Also, too much low gearing won't be good for the D30.

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Good points.

I was out on the trail today and tried to experiment with different gears. I don't think the 4:1 will be too low. Also when plugging both setups into a gear calculator it looks like my current 2nd gear will be in between 3rd and 4th with a 4:1, which isn't bad at all.

Why do you suggest a 4:1 over an auto with a stock low range? I was kind of leaning towards swapping in an auto with a RaDesign's shifter (similar to BrettM's).

I think if I was to go with a doubler I would be biting off more than I can chew. The gear selection and low ratio would be really nice, but being that it's still a daily driver with stock axles it might be a bit much. After spending the day with Toyotas and Cruisers, I'm not afraid to say that I'm jealous of there gearing. An FJ today had a crawl box with a 9:1 low range, and that seemed about perfect.

Starboard M said:

The 4:1 is loud. Much louder then stock. I dont have much of an interior left, and there is a definite gear drone at almost all speeds. I think the max rpm for them is somewhere around 3k rpms, but a quick visit to their site will tell you that.

I ended up going with a used 4:1 with 2low because I got one heck of a good deal on it. It was also nice because it was a bolt in affair. Not having to redo driveshafts, shifter linkage, or floor modifications were big advantages.

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I don't have much carpet left either, but a little whine I could live with. Is it noticeable while in 2wd too?

I've been keeping my eye on all the classifieds from different boards. I found a blemished 4:1 for $899 new, which seems to be pretty good. I'll also be doing a 2 low no matter what option go with.

TORX said:

I don't have much carpet left either, but a little whine I could live with. Is it noticeable while in 2wd too?

I've been keeping my eye on all the classifieds from different boards. I found a blemished 4:1 for $899 new, which seems to be pretty good. I'll also be doing a 2 low no matter what option go with.

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Yes, its noticeable in 2wd. With music, you have to strain to hear it, but Im anal about noises, so I almost strain to hear it to make sure its still making the noise for some stupid reason.

4wd it is really bad. Just chalk it up to Jeep noise, and it makes it all better.

There shouldnt be any noise in 2WD because the planetaries arent moving!I bought mine new 9yrs ago and like I said its a little noisier than stock(in 4lo) but thats it.

Some info regarding RPM's and gear noise with the 4:1.

Teraflex said:

High RPM Warning:
Do not exceed 2500-3000 RPM for sustained periods of time when using the Low231 in low range. Avoid high engine speeds when using the Low231 in low range in 4th or 5th gear with manual transmissions or with high gear automatics. This is common when driving in snow, mud, or sand. Because the gears are turning 50% faster and with the high gear ratio, it is possible for input speeds to reach 6500 RPM and cause damage to the transfer case. We recommend using a lower gear in high-range for higher speeds rather than running the Low231 at extreme RPM’s.

Break-in Procedure for the Tera Low231:
One characteristic of a compound planetary unit, such as the Tera Low231, is the associated gear noise. Following installation of the Low231, you will likely hear noise caused by the gear configuration. This is to be expected of the new gear system and can be reduced by following some simple break-in or adjustment guidelines. Run the vehicle in low-range. A good day on the trail should be sufficient for the gears to quiet down. Running the vehicle in low-range in a parking lot while accelerating and decelerating will also help quiet the gears.The planetary gears idle in all positions except low-range. The more lowrange use the gears experience, the quieter they become in all positions.

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There was/is a thread on Pirate about using the back half of a 231 as a "doubler." I can't find it right now, but with a little sweat equity, it was about a $500 option that gives you 2-low, 7.4 low range, and FWD for digs or limping home.

Steve