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Taking the plunge: NV 241J (241OR) TC swap
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=3&t=39247		 Page 1 of 2
Author:  Troysterr [ Fri Jan 16, 2009 12:28 am ]
Post subject:  Taking the plunge: NV 241J (241OR) TC swap
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):
Image
NV241J:
Image

[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.
Author:  JJsTJ [ Fri Jan 16, 2009 12:38 am ]
Post subject: 
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.
Author:  Troysterr [ Fri Jan 16, 2009 1:42 am ]
Post subject: 
JJsKJ wrote:
New shafts. (or at least I would suggest new ones)

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?

JJsKJ wrote:
Speedo PU is in the rear diff.

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?

JJsKJ wrote:
Your shifter lever will be reversed. Pulled up and back for 2HI and pushed all the way forward for 4LO.

Yeah, that's cool. :) It'll be a reminder that I've got the 241J when I'm not on a trail.
Author:  Wasatch15 [ Fri Jan 16, 2009 8:31 am ]
Post subject: 
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. :D Yes, the Tom Woods front drive shaft has 5 grease points, 3 cardan joints, 1 splined shaft, 1 center ball of CV. :shock:
Author:  JJsTJ [ Fri Jan 16, 2009 11:16 am ]
Post subject: 
Quote:
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?


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!
Author:  Troysterr [ Fri Jan 16, 2009 11:32 am ]
Post subject: 
Thanks! I've updated my original post with this information.

This is going to be a huge help, I really appreciate it.
Author:  HoppedUpOnGoofballs [ Sat Jan 17, 2009 10:51 pm ]
Post subject: 
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.
Author:  Troysterr [ Wed Feb 11, 2009 11:58 pm ]
Post subject: 
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. 8)
Author:  Guest [ Thu Feb 12, 2009 12:32 am ]
Post subject: 
JJsKJ wrote:
Quote:
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?


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!


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.
Author:  tjkj2002 [ Thu Feb 12, 2009 12:40 am ]
Post subject: 
icarl wrote:
JJsKJ wrote:
Quote:
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?


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!


Given that tidbit of info i wonder if you can splice the wiring to use the speedo 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
Author:  Troysterr [ Sat Feb 14, 2009 11:43 pm ]
Post subject: 
tjkj2002 wrote:
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.


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.
Author:  Troysterr [ Sat Feb 14, 2009 11:44 pm ]
Post subject:  Ooh...shiny!
Here's what the innards of my new TC look like, in case anyone cares:

Image
Author:  Guest [ Sat Feb 14, 2009 11:58 pm ]
Post subject: 
Troysterr wrote:
JJsKJ wrote:
Your shifter lever will be reversed. Pulled up and back for 2HI and pushed all the way forward for 4LO.

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


ThunderbirdJunkie would just say

"No, seriously, look-I did that whole trail in 2hi!"
Author:  JJsTJ [ Sun Feb 15, 2009 1:01 pm ]
Post subject: 
Troysterr wrote:
tjkj2002 wrote:
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.


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.


Correct. Won't work in a TJ.
Author:  JJsTJ [ Sun Feb 15, 2009 1:04 pm ]
Post subject: 
ThunderbirdJunkie wrote:
Troysterr wrote:
JJsKJ wrote:
Your shifter lever will be reversed. Pulled up and back for 2HI and pushed all the way forward for 4LO.

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


ThunderbirdJunkie would just say

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


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.
Author:  InCommando [ Sun Feb 15, 2009 9:02 pm ]
Post subject: 
HoppedUpOnGoofballs wrote:
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.


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... :D
Author:  JL Rockies [ Sun Feb 15, 2009 10:22 pm ]
Post subject: 
You should try her out in MOAB this weekend with Durangotang and I.
Author:  Troysterr [ Mon Feb 16, 2009 12:56 am ]
Post subject: 
JJsKJ wrote:
Correct. Won't work in a TJ.

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.
Author:  JJsTJ [ Mon Feb 16, 2009 11:29 am ]
Post subject: 
Troysterr wrote:
JJsKJ wrote:
Correct. Won't work in a TJ.

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. :lol: :wink:
Author:  Troysterr [ Mon Feb 16, 2009 7:52 pm ]
Post subject: 
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. 8) 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.
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