Will a 241 TC (Rock-Trac) fit in the Liberty?

chefdab · **Posted:** Sun Mar 23, 2008 6:42 pm

How much was the raffle ticket that won the t-case? How did you get so lucky?

Troysterr · **Posted:** Sun Mar 23, 2008 7:10 pm

chefdab wrote:

How much was the raffle ticket that won the t-case? How did you get so lucky?

It was free...well, it was included in the $75 that I paid for the EJS registration.

You should go to that raffle some time. They sit there and give away prizes (ranging in value from $200 to $3,000+) for 3-4 straight hours, as fast as they can go.

I heard someone say that your odds of winning something are about 1:4.

They give away things like full lift kits (mostly for Wranglers, of course), Atlas TCs, full axles, sets of Maxxis tires, etc. Something like $200,000 worth of gear.

jason thompson · **Posted:** Sun Mar 23, 2008 7:20 pm

tjkj2002 wrote:

Troysterr wrote:

Yeah, I'm probably better off getting it installed locally. I have to get the TC through my local dealer...I can't wait to their response when I tell them I want it installed in a KJ.

Don't have a dealer install the t-case,they will mess it all up and cost you to much money.Have a good offroad shop or tranny shop do it.

X2

Kugellager · **Posted:** Thu Jul 31, 2008 8:48 pm

Dredging up an old thread.

Hey Troy, I have the NP241J in my KJ (KJ Specs in my sig) and the rear of my t-case looks like the one in the photo you have labeled "Pic of the NV241J(RockTrac)......... " The front half of the housing looks like the one in the first photo except for the bolt pattern/locations. The bolt patten on the two halves is like that of the Rock Trac and so is that at the output-shaft housing with 6 bolts. Also there is no wiring (I assume it's a spedo sensor) protruding from the output-shaft housing.

What gives? Do I have some half-breed transfer case? There is the standard 2.72 gear ratio marking on the case.

John
];')

Below are some photos of my t-case:

http://www.arachnoboards.com/ab/gallery/displayimage.php?imageid=9755

http://www.arachnoboards.com/ab/gallery/displayimage.php?imageid=9756

For whatever reason I cannot get the images to automatically load - sorry.

tjkj2002 · **Posted:** Thu Jul 31, 2008 9:21 pm

Kugellager wrote:

Dredging up an old thread.

Hey Troy, I have the NP241J in my KJ (KJ Specs in my sig) and the rear of my t-case looks like the one in the photo you have labeled "Pic of the NV241J(RockTrac)......... " The front half of the housing looks like the one in the first photo except for the bolt pattern/locations. The bolt patten on the two halves is like that of the Rock Trac and so is that at the output-shaft housing with 6 bolts. Also there is no wiring (I assume it's a spedo sensor) protruding from the output-shaft housing.

What gives? Do I have some half-breed transfer case? There is the standard 2.72 gear ratio marking on the case.

John
];')

Below are some photos of my t-case:

In a sense you do have a half breed t-case,the NP241 is more commonly called the 231HD,it's basically a HD version with a 1/4" wider t-case chain.

Kugellager · **Posted:** Thu Jul 31, 2008 10:21 pm

Read a lot of threads in LOST and other places looking for info on the NP241J. Seems like it is not on all manual transmission KJ's. Wonder why they used it at all? Maybe they only put it on the 6-speed manuals?

Does the NP241J actually have a wider chain or is it just 231 guts in a hybrid case? For that matter, is there any advantage to having the NP241J over the 231 or 242 t-cases seen in most KJ's?

What does this mean for my plans to get a SYE kit in the future?

John
];')

InCommando · **Posted:** Thu Jul 31, 2008 11:38 pm

From what I have found, only the 6-spd KJ's had them. The earlier 5-spds used the 231J.

As near as I can tell, this is equal to a 241C or 241D x-fer used in 1/2-ton trucks BUT There is siad to be a 241HD (in Dodges, for example) that used an even wider chain. I cannot find anything but trash on Wiki that the 241J was ever known officially as a 231HD. 231HD is kind of a slang term that has been applied to it, possibly because it is the Command Trac HD in KJ's.

There are people in the x-fer business who still swear that the 241J as seen in the KJ does not exist, though, and only a 231 & 242 were used. Pics of my x-fer tag are obviously fakes?

Everyone assumes that the spline counts are the same as a 231J, but I do not know anyone who has physically confirmed this.

I do not know the SYE answer, though.

That 241OR sure is sweet, though.

Khaki-KJ · **Posted:** Thu Jul 31, 2008 11:40 pm

It has a larger case that holds more fluid, I suppose that would help keep things cooler.

Kugellager · **Posted:** Fri Aug 01, 2008 12:39 am

InCommando wrote:

There are people in the x-fer business who still swear that the 241J as seen in the KJ does not exist, though, and only a 231 & 242 were used. Pics of my x-fer tag are obviously fakes?

I guess my photos above are fake too LMAO! Whatever! There are several people here who have them and probably more who have never looked on their KJ who do.

Here is the unshrunken crop of the first photo I posted above showing the tag on the transfer case. It's not the sharpest photo but I was taking a photo of the entire case and not focusing on the tag.

http://www.arachnoboards.com/ab/gallery/displayimage.php?imageid=9769

Thanks for the info...the story grows more interesting the more I learn.

John
];')

Khaki-KJ · **Posted:** Fri Aug 01, 2008 1:00 am

Hmm, looks familiar. If my transfer case does not exist, does that mean I am only 2 wheel drive, and if so, which end?? :shock:

jason thompson · **Posted:** Fri Aug 01, 2008 8:05 pm

Kugellager wrote:

Read a lot of threads in LOST and other places looking for info on the NP241J. Seems like it is not on all manual transmission KJ's. Wonder why they used it at all? Maybe they only put it on the 6-speed manuals?

Does the NP241J actually have a wider chain or is it just 231 guts in a hybrid case? For that matter, is there any advantage to having the NP241J over the 231 or 242 t-cases seen in most KJ's?

What does this mean for my plans to get a SYE kit in the future?

John
];')

There is no real advantage to the 241J vs a 231 in a KJ because you will never brake a 231 with a KJ unless you get really stupid but chances are the front diff will explode long before T-case damage

Now there is an advantage to having a 231 over a 241 or a 242 and that is Terra Low gears
you can convert a 231 to have 4 to 1 for <$1k + a drive shaft and for a few $ more have 2wd low provided you do the work your self
This is much cheeper than a rock trac and more than enough for a KJ
even better than 4 to 1 would be 5.44 to 1 and when advanced adapters comes out with there 231 doubler for the 42rle you could just bolt that in

Guest · **Posted:** Fri Aug 01, 2008 9:21 pm

WHOA WAIT, 2LO with a 231?

Where and how?

jason thompson · **Posted:** Sat Aug 02, 2008 7:25 am

ThunderbirdJunkie wrote:

WHOA WAIT, 2LO with a 231?

Where and how?

for ~$200 bucks
here you go
http://www.quadratec.com/products/52254_200.htm

InCommando · **Posted:** Sat Aug 02, 2008 1:35 pm

Deeper x-fer gears are cool because their is no need to change your axle gear ratios & you can still get better performance, but only in low range. If you have taller tires on your rig, you will still have to change your axle gears as well or live with lessened street performance.

By going with deeper gears in the diff, you do not increase the torque until downstream of the diff, mainly to the axles. By going with deeper gears in the x-fer, you add that torque multiplication to the driveshafts, their CV's, and especially the diffs as well as the axles. Going with deeper axle & x-fer gears puts the double whammy on the parts from the diff. out.

I wonder what issues might arise in the D30a and/or the 8.25 with 5.44 gears in the x-fer +/- deeper axle gears? As the 3.7 makes 30 more HP than the 4.0L I6 &, IIRC, 15 more ft. lbs of tq than the 4.0, this might be a bigger issue in the KJ for those reasons alone. Lower gears in the x-fer or a doubler is not the end of the build, but the beginning. Unless you are only putting 70 hp to the ground like a Toyota, you had better plan on further upgrades to your drivetrain.

If there was no advantage to a wider chain & a tougher case, why did they do it? Why did Chevy run a 241 ( with the same chain width as the KJ 241) in a truck instead of a 231? Why is the 241 used in the bigger, heavier JK in place of the 231? Simple: The 241 is in fact a tougher x-fer and even DC, who did not really over-engineer anything when they owned Jeep, felt that the 231 was not up to the shock loads of the 3.7 & the low 1st gear in the 6spd. The 231 may be adequate for the lower-powered & lighter weight TJ, but DC did not spend more money to buy & engineer the 241 into the 6spd KJ's and, from what I have read, all JK's, without a reason. If they did not feel that the tougher x-fer was needed, DC would not have spent a dime to use it. They were only protecting themselves from what they saw as a potential for warranty issues that existed with the 6spds & the JK's had they used the 231.

Kugellager · **Posted:** Sat Aug 02, 2008 3:18 pm

jason thompson wrote:

all very true and good points when you look at the fact's that are printed
"on paper" the 3.7 KJ and 3.8 JK are stronger than a 4.0 TJ
now look at the real world and think about it

Torque specs
TJ 4.0 = 222 LBFT @ 2800 RPM
KJ 3.7 = 235 LBFT @ 4000 RPM
JK 3.8 = 237 LBFT @ 4000 RPM

Horse Power specs
4.0 TJ = 181 @ 4600 RPM
3.7 KJ = 210 @ 5200 RPM
3.8 JK = 202 @ 5200 rpm

A dose of the real world
when out on the trail and climbing an obstacle you need more torque at lower rpm
The 4.0 produces only 13 less ftlb than the 3.7 at "best" but when you are trying to keep rpm down and can get 222 at only 2800 rpm then that is by far better than get an extra 13 ftlb at an extra 1200 rpm

You forget the KJ 3.7L engine has a very flat torque curve and puts out around 220 lb-ft at 2800 rpm and over 200 lb-ft from 1500 rpm on up. So the actual 'real world' difference is minimal.

That said; a stock KJ, I believe, IS heavier that a stock TJ.

John
];')

InCommando · **Posted:** Sat Aug 02, 2008 3:20 pm

Nice catch. Thanks for pointing out the 3.7 equals the 4.0 at most RPM's & exceeds it pretty handily at higher RPM's.

EDIT: The TJ probably weighs 400#'s or so less then a KJ. It depends on stuff like hard top vs soft top, etc...

Khaki-KJ · **Posted:** Sat Aug 02, 2008 3:57 pm

The 241 comes with the manual transmission, no choice, and I paid less for the manual with the 241 than I would have for an auto with the 231. No upsell there, I saved money.

InCommando · **Posted:** Sat Aug 02, 2008 5:00 pm

Another good point! And as the 241 is the base x-fer in the JK, as well.... upsell? Hmmm....

tjkj2002 · **Posted:** Sat Aug 02, 2008 7:17 pm

InCommando wrote:

Another good point! And as the 241 is the base x-fer in the JK, as well.... upsell? Hmmm....

The 241 is needed for the 6-speed tranny's because the 231 does not bolt up to the new 6-speeds.

The RockTrac t-case is a ultra modified 1-ton rated t-case with a 1 1/2" chain,something like twice the width as a 231 t-case.

BeepBeepJeepJeep · **Posted:** Sat Aug 02, 2008 7:49 pm

jason thompson wrote:

ThunderbirdJunkie wrote:

WHOA WAIT, 2LO with a 231?

Where and how?

for ~$200 bucks
here you go
http://www.quadratec.com/products/52254_200.htm

We have the NV231, not the NP231...

Will a 241 TC (Rock-Trac) fit in the Liberty?

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