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Discussion Starter #1
ive heard different stuff on the 207.
in 4hi is it full time? whats the max driving speed?
and 4 lo?
whats the best tc out there and why is it good? and will it work with a 4speed manual asin warner?
 

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Wait you wrote the whole wiki article?! If you did, wow great job, there so much good information in it!
 

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Wait you wrote the whole wiki article?! If you did, wow great job, there so much good information in it!
Ya I actually helped write a lot of those, I am/used to be an admin for JF's wiki. I dont know if I still am since I havent done anything with it in a long while.
 

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Discussion Starter #6
I wrote that article :D

The np207 was just a brother to the np231, but the "Part time" is not designed to be driven on road and I would keep is under about 30mph off road.
ok maybe i dont understand the difference between part and fultime 4wd. some care to break down the differences?
 

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Ok well I'm assuming you aren't going to drop 2 grand on an Atlas II, so I did some research for you.
The 231 is a very popular transfer case that is readily available. According to Novak Jeep Conversions - Home, the ax4 is basically a ax5 w/out the overdrive. The 231 came from the factory behind an ax5, so that means you should be able to put a 231 behind your ax4 with out much trouble. I don't have any personal experience though, just what I am reading online.
 

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ok maybe i dont understand the difference between part and fultime 4wd. some care to break down the differences?
Full time 4wd means you can drive it on the road, well full time, if you want to. The tc acts like a differential, so it won't get ruined if you use 4wd on dry pavement.

Part time 4wd means you can only use it when the road conditions are slippery since the front and rear outputs are locked together.
 

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Discussion Starter #9
Ok well I'm assuming you aren't going to drop 2 grand on an Atlas II, so I did some research for you.
The 231 is a very popular transfer case that is readily available. According to Novak Jeep Conversions - Home, the ax4 is basically a ax5 w/out the overdrive. The 231 came from the factory behind an ax5, so that means you should be able to put a 231 behind your ax4 with out much trouble. I don't have any personal experience though, just what I am reading online.
the wiki says its part time only as well so i geuss np228/229 if they fit.
so are you saying that the full time 4wd just shifts power to the front or back. and that part time is just power to both diffs at the same speed in 4Hi?locked? as in both tires are locks front and rear? or just front? locked to me means like a locker. i always thought anything with 4h was for road use
 

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Full time 4wd means you can drive it on the road, well full time, if you want to. The tc acts like a differential, so it won't get ruined if you use 4wd on dry pavement.

Part time 4wd means you can only use it when the road conditions are slippery since the front and rear outputs are locked together.
Yes that is exactly it.
 

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the wiki says its part time only as well so i geuss np228/229 if they fit.
Wait what?


Ok full time 4wd, the tc acts just like an open differential. On a straight and perfectly even road surface it transfers equal power to the front and rear. But if one tire looses traction, like on ice, mud, etc, (no matter if its in the front or rear) then all the power will go to that tire and it will spin.

Part time 4wd, the tc acts like a locked differential. The power is transfered 50/50 evenly between the front and rear. Even if say the rear looses traction, power will sill go to the front.
 

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Discussion Starter #12
Yes that is exactly it.
so why would it ruin the transfer cas if both front and rear are spinning at the same speed?neither axles have posi right?
so i dont get why its such a bad tc.
 

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so why would it ruin the transfer cas if both front and rear are spinning at the same speed?neither axles have posi right?
so i dont get why its such a bad tc.
Because when you go around a corner, your front and rear tires spin at a different speed. If your tc is locked, then it does not allow the tires to spin at different speeds. If you just do it once or twice there's no harm, but if driven constanly in 4wd on dry pavement, then it wil cause problems.
 

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Discussion Starter #14
Wait what?


Ok full time 4wd, the tc acts just like an open differential. On a straight and perfectly even road surface it transfers equal power to the front and rear. But if one tire looses traction, like on ice, mud, etc, (no matter if its in the front or rear) then all the power will go to that tire and it will spin.

Part time 4wd, the tc acts like a locked differential. The power is transfered 50/50 evenly between the front and rear. Even if say the rear looses traction, power will sill go to the front.
i gotcha. thats what i thought. thats the only 4wd i know about. i thought part time was it only goes into 4wd when is feels the need lol! anyways kinda like fulltime. im good with my part time then, just as long as i can fix my coupler vac issue. thanks man i understand it now guys
 

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so why would it ruin the transfer cas if both front and rear are spinning at the same speed?neither axles have posi right?
so i dont get why its such a bad tc.
You will begin to put a lot of stress on a lot of parts that dont want a lot of stress. There needs to be give somewhere.
 

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Discussion Starter #16
You will begin to put a lot of stress on a lot of parts that dont want a lot of stress. There needs to be give somewhere.
i always thought that only applied to 4 low. now in 4 low are both diffs at the same ratio?
 

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Discussion Starter #17
some xj guys were saying the 207 is a stronger case. i could see whee there are more stuff to go wrong with a full time 4 unit. but i heard on here that my 207 is crap but wheeln guys say its the stronger, but that most people like fulltime for road driving.i dont see how fulltime would help wheelin. besides most of the time i dont put my jeep in 4wd when i am wheeling,lol!
 

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i always thought that only applied to 4 low. now in 4 low are both diffs at the same ratio?
Part time 4wd and 4 low are the same, except that 4 low has a lower gear ratio (obviously). You would still put stress on the tc is you use part time 4wd on dry pavement.

some xj guys were saying the 207 is a stronger case. i could see whee there are more stuff to go wrong with a full time 4 unit. but i heard on here that my 207 is crap but wheeln guys say its the stronger, but that most people like fulltime for road driving.i dont see how fulltime would help wheelin. besides most of the time i dont put my jeep in 4wd when i am wheeling,lol!
According to this site The New Process 207 Transfer Case - Novak Conversions, the 207 is a medium duty case. It has a wider chain but less gear mesh than the 231. For your application I think it's fine.

And you are correct, 4wd full is not nearly as good as part time 4wd part time off road.
 

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Discussion Starter #19
well if it breaks you think the 231 is the best step up or only other one that fits huh?im tryn to take good car of this jeep. and when the 2.5l finally goes ill get her a nice 4.0l :) im working slowly on it and since its a 2 door i plan on keeping it
 

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The description here of operation of the full-time cases is not entirely accurate. Yes... they are torque-biasing cases. But.. they are not 100% bias cases. Meaning they don't either drive both axles or put all the power to one axle or the other.

When you have full-time engaged and one axle begins slip, the case sends more of the power to that axle, but a portion still is going to the other axle. This allows the Jeep to continue to move forward(or in reverse). The actual operation is much the same as a limited slip axle. When on a combined surface, you can easily feel the system operating. A good example of a combined surface is a snow/slushy road, where you go from snow cover to bare/wet pavement and back.

Now how this compares to the part time cases (NP207/NP 231) is this. The full-time cases have a center axle disconnect in the case, where as the part-time cases don't. When you put your part time case in one of the 4wd settings, it is an almost true 50/50 torque bias with the power being divided between the axles. Now when you place the full-time cases into 4wd low, it locks the case into an almost 50/50 torque bias making it operate the same as the part-time cases in 4wd low.

The reason that you should not operate the part-time cases in either 4wd position of dry pavement is that the case needs to have a bit of traction slip to not cause internal binding and damage. The central axle disconnect is how the full-time cases avoid this. The CAD allows for the slip inside of it and prevents the binding issues.

Two quick advantages of the NP-231 over the NP-207. First a slightly better low range gear reduction of 2.72 compared to the 2.6 of the NP-207. Also the aftermarket for the NP-231 is ALOT better than that of the NP-207.

I can't speak for anyone elses off-road habits, but when I wheel the T-case is always in 4-low. I would rather have the additional torque rather than the wheel speed.
 
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