Lower Range Transfer Case

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Zink.brody
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Lower Range Transfer Case

Postby Zink.brody » Sat Jul 06, 2019 8:27 pm

I want to start by mentioning I did use the search bar haha. I am looking for my options to either double the transfer case or a bolt in option using 4:1 aftermarket gears. I have a 360/tf727/229. I know about the atlas (too much $$$) Dana 300 (hard to get flip kit and $$ for 4:1 and flip). I am wondering what options I have to keep my drivers drop but have a better case then the 229? I play in the rocks a lot.

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KJ Ryu
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Re: Lower Range Transfer Case

Postby KJ Ryu » Sun Jul 07, 2019 8:51 am

I think an NP241OR will bolt up. Might require driveline mods, though.
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rocklaurence
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Re: Lower Range Transfer Case

Postby rocklaurence » Sun Jul 07, 2019 7:28 pm

KJ Ryu wrote:I think an NP241OR will bolt up. Might require driveline mods, though.


Jeep NV241 should bolt up but it may require a 7/8" spacer between the 727 and 241. Drive shafts will likely need changed as well.

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derf
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Re: Lower Range Transfer Case

Postby derf » Mon Jul 08, 2019 7:16 am

The 241OR is a good candidate if you can find one. They are not common used and they tend to sell fast when they are advertised. And they aren't cheap either. Expect to drop over $1K for one in good shape. Sometimes over $2K. If someone hasn't beaten you to it.

You'll want one from 2006 or older. The 2007-2018 JK Wranglers as well as the 2018+ JL Wranglers don't have a provision for the speedometer sender. They switched over to using the ABS sensors to run the speedometer in 2007. If you don't care about running a speedometer, you can run a 2007-2018 JK case but make sure you don't get one from a 2012+ with an automatic. They have a different input shaft that isn't anywhere near compatible. I don't know if the new generation Wranglers (2018+) have a compatible input shaft either way.

I will also say you may need a spacer of some kind because Jeep changed the stick-out of the input shaft over the years.

If you go with 2007+ you'll want to swap yokes on the transfer case to a traditional U-Joint/double cardan CV joint. Jeep switched over to a crappy CV joint on the 2007+ Wranglers that isn't worth using. But it's easy enough to bolt on a different yoke from some place like Tom Woods.

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will e
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Re: Lower Range Transfer Case

Postby will e » Mon Jul 08, 2019 8:57 am

I have the Atlas 4 speed. 2,2.72,5.44. I picked it up used, although it had never been installed. I got a good price by watching Pirate. Took several months but one finally showed up. I got it pretty cheap too. The trick is patience and have the money ready.

I really like the Atlas 4 speed. 2 to 1 is great for easy trails, running washes, etc. 5.44 is plenty low for crawling up stuff. I like the twin shift abilities as well. Rear wheel driveonly in 2 to 1 while going through washes is pretty fun.
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Zink.brody
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Re: Lower Range Transfer Case

Postby Zink.brody » Mon Jul 08, 2019 12:01 pm

Thanks guys I will definitely look into the 241or cases!

Zink.brody
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Re: Lower Range Transfer Case

Postby Zink.brody » Wed Jul 17, 2019 12:53 pm

Has anyone tried out a NWF doubler?

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Stuka
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Re: Lower Range Transfer Case

Postby Stuka » Wed Jul 17, 2019 3:35 pm

derf wrote:I don't know if the new generation Wranglers (2018+) have a compatible input shaft either way.

I will also say you may need a spacer of some kind because Jeep changed the stick-out of the input shaft over the years.

If you go with 2007+ you'll want to swap yokes on the transfer case to a traditional U-Joint/double cardan CV joint. Jeep switched over to a crappy CV joint on the 2007+ Wranglers that isn't worth using. But it's easy enough to bolt on a different yoke from some place like Tom Woods.


The JL's don't use an NV t-case anymore. They switched to using a case from Magna.

The Rzeppa (CV) found on the JK cases is actually heaps stronger than a 1310 u-joint. The weak spot is the junk thin walled tube that the stock drive shafts use, and their max operating angle is slightly less than a u-joint. Although the Rzeppa joint can run at full angle all day without vibrations, where as a u-joint cannot. But you can easily get yokes for cardan style joints from places like Tom Woods.

Zink.brody wrote:Has anyone tried out a NWF doubler?


I have not used one, but it should in theory work if you have an '80+ FSJ. It should be able to fit between the transmission and transfercase. HOWEVER, I would NOT put one of these in front of an NP229. If I was going to get this, I would find an NV241 to go behind it.
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Zink.brody
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Re: Lower Range Transfer Case

Postby Zink.brody » Wed Jul 17, 2019 4:09 pm

Zink.brody wrote:Has anyone tried out a NWF doubler?


I have not used one, but it should in theory work if you have an '80+ FSJ. It should be able to fit between the transmission and transfercase. HOWEVER, I would NOT put one of these in front of an NP229. If I was going to get this, I would find an NV241 to go behind it.[/quote]

In theory then the np 229 and nv241 would be interchangeable behind the nwf doubler?

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derf
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Re: Lower Range Transfer Case

Postby derf » Wed Jul 17, 2019 9:51 pm

Stuka wrote:The JL's don't use an NV t-case anymore. They switched to using a case from Magna.


Magna has owned what's left of New Process Gear for quite a while now. They shut down the plant in Michigan back in 2012.

I would believe the JL has a new generation case with a Magna logo and part number on it.

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Stuka
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Re: Lower Range Transfer Case

Postby Stuka » Thu Jul 18, 2019 6:48 am

derf wrote:
Stuka wrote:The JL's don't use an NV t-case anymore. They switched to using a case from Magna.


Magna has owned what's left of New Process Gear for quite a while now. They shut down the plant in Michigan back in 2012.

I would believe the JL has a new generation case with a Magna logo and part number on it.


Yeah, I see that now. After a bit of reading there are some differences, mostly because the JL has the FAD unit and the t-case has some changes to work with that (extra synchros for shifting).

I am sure the input is different because of the ZF trans used.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
2017 JKU Rubicon Lifted and stuff
Pevious Jeeps: 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

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derf
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Re: Lower Range Transfer Case

Postby derf » Thu Jul 18, 2019 6:56 am

Stuka wrote:Yeah, I see that now. After a bit of reading there are some differences, mostly because the JL has the FAD unit and the t-case has some changes to work with that (extra synchros for shifting).

I am sure the input is different because of the ZF trans used.


It's hard to find the exact part numbers for the JL transfer cases. Either that or my Google-fu is letting me down. They use the trademark names (Command-Trac, Rock-Trac, Selec-Trac) in the documentation instead of the t-case model numbers. But I wouldn't be surprised that there are differences in the new generation cases. The JL Sahara gets a full time capable transfer case so that's probably "new". Though it's probably an adaptation of the full time cases that Chevy has been using for several years now.

The NV241 in the JK has a different input shaft for the 2012-2018 automatic transmission. So they were already making changes back then. It's hard to keep track of it all.


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