As I posted previously, I won a Rock-Trac NV 241J transfer case at the Easter Jeep Safari in Moab last year. It's been sitting in my garage since then (still in the crate...I haven't even looked at it) since then.

I found a pretty good shop, I hope, to install it, so I'm going to try to get that done soon.

What I know:

• The 241J is larger than the stock 231J, so the stock drive lines (front and rear) won't work.
• Troy (tjkj2002) says I'll need a new front D30A yoke/seal.
• Aside from that, according to Dje Ryu (thanks, man), "The 241OR is a replacement transfercase that has the same mounting and input gear..."

On another site, I found a post that says, "The only thing I need to chase down is a connector for the speed sensor. It looks like Jeep changed the connector type and I am going to have to fab something." I can see something that looks like that in these pics (provided by tjkj2002--thanks, Troy):

NP241 (231HD):

NV241J:


[Edit: According to JJ's post below, this connector can be left alone.]

Another question:
Can the stock shafts be shortened and modified to fit the new TC? Or do I have to have custom shafts built?

Since Tom Woods is just down the street (in Ogden), it probably wouldn't be too hard to get them to make some new shafts, per whatever specifications I need. But I read somewhere that the Tom Woods shafts have like 5 grease zerks...and I assume that some of those are tucked under the skid. I wouldn't want to be removing my skids 2-3 times a year.

Does anyone know offhand how I would describe to Tom Woods what I need (aside from the length, which I'll have to measure)?

So, parts list:

• Modified or new front drive shaft (Tom Woods)
• Modified or new rear drive shaft (Tom Woods)
• New u-joints (I assume I'd want these replaced)
• New yoke for front D30A differential: Spicer 2-4-6901 (Tom Woods)
• New oil seal for D30A: Spicer 50619 (Tom Woods)

Anything else (aside from fluids and stuff)?

Unfortunately, I won't be able to take pics of the install, since I'm having someone else do it, and I'm swamped with work, etc. But I'll let you know how it goes, and try to keep track of any additional parts/modifications that are needed.

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09 Yellow JK Rubicon LOST #TY050608
TeraFlex 4" long arm lift, 35" BFG KO2s, Tatton driveshaft, Riddler diff covers, RIPP headers,
MBRP off road exhaust, Cobra C75WXST, Little Passengers 3rd row seat
Formerly: 02 White Ltd 4x4 with lots of stuff...
Pics: http://troysterr.com Links & Parts: http://youngs.org/kjparts

New shafts. (or at least I would suggest new ones)
Speedo PU is in the rear diff.
Your shifter lever will be reversed. Pulled up and back for 2HI and pushed all the way forward for 4LO.

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99 TJ
71 C101
04 KJ
03 SFA KJ Sport
LOST JEEPS So-Cal

That's probably a good idea...I understand that the 4:1 ratio in the 241J might be too much for the stock shafts. Better safe than sorry. I think new shafts from Tom Woods are about $200 apiece. Does that sound about right?


I wonder what those wires are for coming out of the TCs in the picture. Maybe a sensor to tell you what gear you're actually in?


Yeah, that's cool. It'll be a reminder that I've got the 241J when I'm not on a trail.

The yoke you will need for the front D30A differential is a Spicer 2-4-6901. The oil seal is a Spicer 50619. You can get both from Tom Woods. If you go visit them, they will be able to help you through measuring for new drive shafts. Josh (at Tom Woods) worked great for me. Yes, the Tom Woods front drive shaft has 5 grease points, 3 cardan joints, 1 splined shaft, 1 center ball of CV.

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2002 Silver Sport 4x4 3.7L-5 Speed NV3550 Manual Transmission-NV231J TC-Frankenlift-AllJ Interior Rack-ARB Bumper-Hella Driving Lights-Electric Trailer Brake-Moog LBJs-JBA 4.5 UCAs-Detroit Trutrac (Front)-245/70/16 Dueler A/T Tires-Amsoil EaA201 Air Filter-Tom Woods Custom Front Drive Shaft-Rock Lizard Gecko HD Roof Rails-Onboard Co2

The TJ uses the transfer case pickup for the speedo. Since it is not compatible w/ the KJ (different wiring arrangement, etc.) you just need to plug the hole which can be done w/ the actual pickup, just leave it there and don't worry about connecting it to anything. Your speedo won't change as it still picks up its signal from the rear diff.

BadaBing!

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99 TJ
71 C101
04 KJ
03 SFA KJ Sport
LOST JEEPS So-Cal

Thanks! I've updated my original post with this information.

This is going to be a huge help, I really appreciate it.

The only thing I can add is that the first pic looks nothing like an NP241.. NP241 case is ribbed like the second pic.

Other than that, I have nothing.. Good luck. Post pics.

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A Jeep and a couple Fords.


I would wreck Kate Hudson.

Well, the old girl is in the shop and the swap is under way.

This isn't exactly a bolt-in operation. There's an engine mount that they had to modify to fit the new TC in (sorry, I don't have pics or a better explanation of what they had to do...but they said it wasn't a big deal). So, it's a bigger job than I could have handled myself, but this shop specializes in restorations (VW vans, specifically), so this kind of mod is pretty easy for them.

The TC is, apparently, from a JK Rubicon, not a standard Wrangler Rubicon, so they had to swap out both the front and rear yokes (instead of just the front), but Josh at Tom Wood's offered me $50 for both of the old yokes, so that cut the cost down.

It looks like the total cost, including new yokes, diff seal, front and rear drive shafts, and labor are going to come to $1,000-1,200. I'll let you know what the actual damage is once it's done.

So far, I'm very pleased with both the auto shop (McNeil's Auto Care in Sandy) and Tom Wood's. (Of course, Tom Wood's has a great reputation nationwide, so that isn't surprising.)

The work should be done when I get back from Tucson on Monday...in plenty of time to test it in Moab in March and April.

Given that tidbit of info i wonder if you can splice the wiring to use the speed sensor in the new tc and hook it up to the kj speedo. Then you can throw a d44 in the rear and not have to worry about the speedo issue.

Unfortunately you can't.The TJ uses a 3-wire Hall Effect sensor for the speedo,the KJ uses a 2-wire A/C signal generator to operate the speedo.

See this post for the fix if not using the OEM rear axle--http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=29930

So...does that mean I can't sell my old NV231 to a TJ guy? Or do only Rubicon TJs use the 3-wire connector on the TC?

There's a guy that's interested in buying my old TC, but he has a TJ.

Here's what the innards of my new TC look like, in case anyone cares:

ThunderbirdJunkie would just say

"No, seriously, look-I did that whole trail in 2hi!"

Correct. Won't work in a TJ.

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99 TJ
71 C101
04 KJ
03 SFA KJ Sport
LOST JEEPS So-Cal

That happened to me yesterday wheeling in the snow trying to pull a long hill. Passenger hopped in to add some weight and commented: "no wonder you can't get up the hill, you are in 2wd" I lol'd at him and explained the situation. fun times.

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99 TJ
71 C101
04 KJ
03 SFA KJ Sport
LOST JEEPS So-Cal

You are absolutely right. People make that mistake all of the time, too. The only thing I have seen pics of that looks like the OR is a 241D-HD. Outside of people talking on jeep boards, I have never seen anything official calling a 241J a 231J-hd. Chevy doesn't call a 241C a 231c-hd, Dodge does not call a 241d a 231d-hd, and I'll bet the makers of these transfers do not call them that, either. Oh well. I guess the 241d-HD is actually a 231d-HD-HD...

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LOST # 633
'05 KJ 3.7L/6spd/241 245/75/16 MT's
'88 MJ 4.0L/AW4/231 SWB HPD30 & trac-loc D44 w/3.73's
A dirty Jeep is a happy Jeep

You should try her out in MOAB this weekend with Durangotang and I.

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2006 CRD http://www.UtahPowderCoatings.com/ http://www.gorecon.com/ I'm kind of a big deal.
RL rear bumper, ARB front bumper, Mile Marker winch, Power Tank, Skids by Mopar & Skid Row, RL Super Skink Sliders, 235/85R16 MTR, Air Flow Snorkel, DTT, 4.10 gears, Frankenlift II, Katskin leather, JL Audio stereo, Rosen video.

That's a bummer--sort of restricts the number of people I can sell this thing to. I can see a lot of old TJs and KJs needing new t-cases, but there probably aren't a whole lot of worn out NV231s in KJs out there. These things tend to last a long time.

Yeah I have my old one and just keeping it as a spare for my wifes kj in case i ever need it. found out they are not worth much yet since only fits a kj and since we are only mall crawlers, we never break stuff.

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99 TJ
71 C101
04 KJ
03 SFA KJ Sport
LOST JEEPS So-Cal

It's all done. Total damage:

• Rock-Trac transfer case: $0
• Tom Wood's front drive shaft + CV yoke: $375
• Tom Wood's rear drive shaft + CV yoke: $375
• Spicer U-joint 5-134X: $26
• Labor - TC remove and replace: $207
• Labor - Measure for drivelines, modify transmission mount, replace yokes, install axles: $263
• Total: ~ $1,250 + tax

All of that for an entirely unnecessary modification. Don't you love Jeeping?

On the bright side, if I ever decide to do an SFA swap, I'll already have a workable transfer case that would have cost me over $2,000.