NP231J Transfer Case Kit?
Thread Starter
Junior Member
Joined: Mar 2009
Posts: 41
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Year: '85
Model: Cherokee
Engine: 4.0L I6
Can anyone tell me where to start looking for a kit i can install in my transfer case? i am looking for lower gearing. just took it out for a test run and it's not geared enough.
CF Veteran
Joined: Nov 2008
Posts: 1,251
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From: Eugene, OR
Year: 01
Model: Cherokee
Engine: 4.0L I6
i think tera-low makes something like that.
edit: found this
http://jeep.off-road.com/jeep/articl....jsp?id=259037
edit: found this
http://jeep.off-road.com/jeep/articl....jsp?id=259037
Thread Starter
Junior Member
Joined: Mar 2009
Posts: 41
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Year: '85
Model: Cherokee
Engine: 4.0L I6
k change in plans...i now have a NP207 transfer case and am looking for a gearing kit for it...all i need is replacement gears to put in place of the one i already have not an entire transfer case...any ideas on where to start looking? my jeep is an 85 2.5L with the T4 tranny and the NP207 transfer case. i'm already runnin 4.10 gears in the the axles. if they dont make a kit for the transfer case what transfer case could i bolt up to my existing tranny to give me better gearing?
i think tera-low makes something like that.
edit: found this
http://jeep.off-road.com/jeep/articl....jsp?id=259037
edit: found this
http://jeep.off-road.com/jeep/articl....jsp?id=259037
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Yeah, I would do the same, the 231's are really good t-cases, they last forever as long as you don't smash them hell out of them on rocks. Plus they are easy to get parts for because they have been around for so long.
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Joined: Nov 2008
Posts: 2,473
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From: Paso Robles Ca
Year: 1991
Model: Cherokee
Engine: 4.0
Thread Starter
Junior Member
Joined: Mar 2009
Posts: 41
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Year: '85
Model: Cherokee
Engine: 4.0L I6
i'm runnin the 2.5L and 410 gearing in the axles but the 2.5 doesn't have enough power to push my 31x10.50 tires up some of the **** i'm goin through. i have to ride my clutch up the steepest ****. i have the 207 currently in my jeep but can aquire a 231...is it cost worthy to put the 231 in seein how there really isn't much of a gearing difference?
you want a LONG input 21 spline np231.
an np207 isn't a t-case recommended for longevity, even behind a 4 cylinder.
also, chances of you having a T4 in your jeep are about 3/100 if even that. Just making you aware that it's an Ax4 more likely than a T4 as T4's were only used by jeep when the ax4's ran out on the production line.
furthermore, you are going the wrong way about this. your 4 popper doesn't have the power to push the 31's because your AXLE gearing is too high. you should be at 4.56 or 4.88 with that size tire.
they don't make "gear kits" for your np231, other than the Tera kit. if you're bent on working the t-case around the gears instead of the axles, what you're looking for is a transfercase doubler such as the Box4Rocks np231 doubler kit. for this you'd need new front and rear driveshafts made, and to have a spare front section of an np231 with the main gear assembly in it.
that option would be more expensive than regearing the axles (once you get done spending $450 on driveshafts that is), but would give you a combination of
(L meaning low and H meaning hi)
2h 2h
2L 2h
2L 2L
4h 4h
4h 4L
4L 4L
as well as N N
there are several variances of those selection options which equate to the same output. I forget the lowest crawl ratio you can get out of them but it's something like 173:1
you'd profit greatlly from the combination, but in the end it's just two np231's and would cost about a grand all said and done not to mention the time involved plus having to make new t-case linkages.
an np207 isn't a t-case recommended for longevity, even behind a 4 cylinder.
also, chances of you having a T4 in your jeep are about 3/100 if even that. Just making you aware that it's an Ax4 more likely than a T4 as T4's were only used by jeep when the ax4's ran out on the production line.
furthermore, you are going the wrong way about this. your 4 popper doesn't have the power to push the 31's because your AXLE gearing is too high. you should be at 4.56 or 4.88 with that size tire.
they don't make "gear kits" for your np231, other than the Tera kit. if you're bent on working the t-case around the gears instead of the axles, what you're looking for is a transfercase doubler such as the Box4Rocks np231 doubler kit. for this you'd need new front and rear driveshafts made, and to have a spare front section of an np231 with the main gear assembly in it.
that option would be more expensive than regearing the axles (once you get done spending $450 on driveshafts that is), but would give you a combination of
(L meaning low and H meaning hi)
2h 2h
2L 2h
2L 2L
4h 4h
4h 4L
4L 4L
as well as N N
there are several variances of those selection options which equate to the same output. I forget the lowest crawl ratio you can get out of them but it's something like 173:1
you'd profit greatlly from the combination, but in the end it's just two np231's and would cost about a grand all said and done not to mention the time involved plus having to make new t-case linkages.
Thread Starter
Junior Member
Joined: Mar 2009
Posts: 41
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Year: '85
Model: Cherokee
Engine: 4.0L I6
k i appreciate the input. now you got me thinkin though. where's the best place to start lookin for new axle gears...keep in mind i'm kinda on a tight budget.



I don't have any info yet.