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Transfer case options???????

Explorer 1

NAXJA Forum User
Location
Whittier, Ca
I have a 1990 XJ, 4.6 Golen Stroker, AW4 Trans, NP-242 Transfer Case, 4.5" short arm lift, Front & Rear ARB, Rear-Currie, Rock-Jock 60, Front-Dana 30 Chromoly axles, 4.88 gearing on BFG 35x12.50 tires.

When installing the new rear axle I debated changing to a 5.13 ratio, I would rather seek a transfer case that woul dprovide me the exta low gearing for the low range but still allow the high range for my freeway speeds.

Wondering if anyone out there can enlighten me on what is available, or am I lookimg for something that doesn't exist?

My friend just installed a "crawlbox" on his Toyota that allows him to keep same high 2wd ratio but use the new "box" for those tougher rock sections.

Thanks in advance for any help!

Fred
Explore 1
 
quoted from CherokeeForum:

For comparison purposes only:
A TeraFlex 4 to 1 kit replaces the front half of a 231J case and uses a 6 planetary low range.
Cost is $1000-$1200

A RockTrack NP241OR (Rubicon) T-case used is going to be pricey as well. I looked at a few and found out all of the used ones are made out of gold, platinum, and unobtainium. These t-cases also use a 6 planetary low range. Be careful buying a used one though. Stretched chains seem to be rather common and a new replacement is going to set you back around $300.
Cost $850-$1700

Atlas T-cases are the shizz! Truly a solid upgrade for those that need the beef, but the simple fact is that most of us don't need that kind of strength and features of an Atlas T-case.
Cost $2000-$2300, not including shifters, linkage, brackets, etc.

The cost beefing up an OEM NP231J with easily obtainable JY parts is going to vary by area, obviously some JY's are more expensive than others. My local JY gets $75 for a complete t-case, any flavor. Tear it down in the yard and the price for the individual parts needed is a lot less.
Estimated Cost for beefing up a 231J?
$50-$200

the last option is cheaper, but you dont gain the extra low gearing that you are looking for.

hope this helps.
 
There are several options available, none of which are real cheap.

First is add either an NP231 doubler, the planetary portion of an NP 231 or a Klune V and floor modifications. Personally, I like the Klune V better. It comes in either 2.7 or 4.0 ratios. With the 4.0 you would have the equivalent of the Atlas 4 speed with 1:1, 2.7:1, 4.0:1 and 10.8:1

You can add either box to a flipped Dana 300 which has a 2.0 ratio. With the 2.7 Klune V or doubler, you would have 1:1, 2.0:1, 2.7:1, 5.4:1 or 1:1, 2.0:1, 4.0:1, 8.0:1

You can put out some bucks for a Stak 3 speed that has ratios available up to 5.44:1

With floor modification you can also use an Atlas 4 speed with ratios up to 10.38:1

That is what I have, it works very well and I have no complaints about it.
 
change t.c, for best of both world's !!! ?? if you are going to change axle gear's go 5.38's ! i did 5.13's and it's not enough ! with 37's
 
I paid 800 bucks for my RockTrac 241OR Rubi case freshly re-built, with a warranty from Mantrans), and havent looked back since. You can find them, they are out there. The case on a 241 is twice as thick as a 231 case, bigger chain, etc etc. Its not just the 4:1 you are getting, you are getting a MUCH beefier case and components.

~ Stump
 
quoted from CherokeeForum:



the last option is cheaper, but you dont gain the extra low gearing that you are looking for.

hope this helps.
gotta love the bs info on cherokee forum, fyi atlas will cost you 2300 with 32 spline frt output(why would you buy a atlas and not get it), shifters come at no extra charge, and not to mention you will never have to worry about your tcase ever again
 
check out duff on pirate, they make a kit called box4rocs u use the planitery of the 231, aka the front half, weld on a aluminum backing plate, an the output from the 231 goes into the input of ur flipped d300, an if u 4:1 ur d300 (assumiong u buy the d300, an drop the 500 ont the kit) that would give u a few good gear choices, an front digs ftw
 
Thanks for all the great advice,

I'm doing some serious looking at the Klune V "David".

Anyone had actual experience with this in their XJ. I would be moving over to a "built" NP231 at the same time.

Thanks,
Fred
Explorer 1
 
Atlas 4 speed gives you 2.00:1, 2.72:1 and 5.44:1. With my AW4, 4.56 and 35's I have to give it gas to go downhill and you still have the 2.00:1 for the fast stuff. You have a Rock Jock so I know you are not afraid to spend the money.
 
Thanks for all the great advice,

I'm doing some serious looking at the Klune V "David".

Anyone had actual experience with this in their XJ. I would be moving over to a "built" NP231 at the same time.

Thanks,
Fred
Explorer 1

Atlas 4 speed gives you 2.00:1, 2.72:1 and 5.44:1. With my AW4, 4.56 and 35's I have to give it gas to go downhill and you still have the 2.00:1 for the fast stuff. You have a Rock Jock so I know you are not afraid to spend the money.

Bear in mind that with either of these options you will have to modify the tunnel to accommodate the longer gear boxes. Personally, if you are going to build a 231, you would be better off building a D300 with a flip kit. I have always heard goo things about the Klune boxes.
 
I had an Atlas 4.3 in my last rig and loved it. They are more than $2300 delivered now though.
Is it worth it for a 80-90% street driven rig? That is your call....
When I got the XJ, I toyed with getting an Atlas, Stak, Klune under drive, 241 from a Rubi, doubler and the 4:1 kit from Tera.
I actually bought a Klune for reasonable money, but I would have had to move all my long arm mounts to make it work right so I sold it.
Atlas' are too much for a DD'd rig IMO, unless money is not an issue.
I went with a Teralo kit and never looked back,. I got it from 4x4 groupbuy for just under $800 delivered IIRC.
There are some places where 4:1 is too low and 1:1 is too high, but I deal with it:cool: I had the same issue with the Atlas too. Only way around that is to use a doubler/Klune/4 speed. I though about the doubler as I have a Dana 300 I could have used, but the extra mods were not worth the gain to me.
Coming from someone who has gone the Atlas route before, the Teralo kit worked out great for me at under $1k installed. Remember with ALL the other options there are other mods to make too....

Martin
 
Regarding tunnel mods, my atlas 4sp required a very minor dent hammered into one place. I got mine for $2725 to the door. For me it was in the cards at the time, and it was worth every penny to me. With some innovation and elbow grease, you can get similar gearing for a lot less, but I don't regret it :looney:
But, I have an AX15. With an auto, I think you would probably be happy with a 4:1, keeping the 4.88s you have. Don't bother with the 5.13's, since you can't get them for the D30, and it would only be a 5% reduction if you did. It would make a very minor difference.
 
Regarding tunnel mods, my atlas 4sp required a very minor dent hammered into one place. I got mine for $2725 to the door. For me it was in the cards at the time, and it was worth every penny to me. With some innovation and elbow grease, you can get similar gearing for a lot less, but I don't regret it :looney:
But, I have an AX15. With an auto, I think you would probably be happy with a 4:1, keeping the 4.88s you have. Don't bother with the 5.13's, since you can't get them for the D30, and it would only be a 5% reduction if you did. It would make a very minor difference.

Mine fit without anything major, but my tranny is shorter than an AW4 and the engine sits a couple of inches forward too. AA says that with the AW4 the 4 speed takes some modification, I agree with them. But it is not that difficult. It just depends on what you want to live without. I was lucky enough to have it look completely stock except for the extra shifters in the console.
 
Thanks guys,

I considered the Atlas, as I have one in my SMB, however, my understanding is that Atlas does not recommend flat towing with their transfer case, which I do each year a couple of times.

I've done some reading about the mods necessary with a Klune V and they don't seem out of line with the other mods I have alreday made. I may end up machining my own linkage unless someone alreday has addressed this in a good manner.

I an curious about the NP300 and what advantages it would have over the built up 231 I am considering.

Thanks,
Fred
Explorer 1
 
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