Author Topic: transfer case swap  (Read 4547 times)

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Offline brokenwrist21

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transfer case swap
« on: November 30, 2012, 12:25:59 PM »
Hey guys, it's been awhile since I've been on. Anyway I was going to do a 2wd low kit and sye in my 231 thats in my wrangler, but after reading up and talking to my boss I have figured out that swapping in a 241or makes more sense. I'm thinking about this for the same reasons it was put in the rubicons, 4:1 low range and fixed yoke output. My concerns are, 1. are the bolt patterns the same? and 2. will my shift linkage work or will I  have to use the 241 linkage with my shifter?
'93 yj 4in rubicon express lift, 33" bfg mud terrains, yella terra roller rockers, 4.0l throttle body, rv cam, k&n air filter, yukon axles and gears, detroit locker, aluminum radiator, msd 8.5mm super conductor wires, full syn. fluids.

Offline Jeffy

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Re: transfer case swap
« Reply #1 on: November 30, 2012, 02:57:18 PM »
Spline count on the input shaft will be your hurdle.  A 2.5L manual uses a 21 Spline, IIRC.  241OR will be 23 Spline.
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Offline jagular7

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Re: transfer case swap
« Reply #2 on: November 30, 2012, 04:07:44 PM »
You are wanting to install into what model Jeep, and which trans? Auto TJs have 23-spline output. If other than TJ with auto, as stated, spline count will be an issue. Another may be the floor in a YJ since the overall size (diameter) is larger than the normal 231. The shift linkage shouldn't be an issue connecting, but adjustment will be necessary. That's not a problem, just something you have to do. Next, like you stated, fixed yoke. However, Rocktracs are not yoked, they are flanged. You could get a yoke or keep the flange. Next, while getting the Rocktrac, look for the rear ds since it will bolt to the flange. You may have to change the yoke on the rear axle to mate to the yoke series of the stock TJ Rubicon tcase. Now, I'm assuming the Rocktrac you are looking for is from a TJ and not the JK. The JK is similar but alas another different case....lol.
Next, depending on your year Jeep model, the TJ Rocktrac has an electronic speedo sensor and not the regular mechanical speedo. Lastly, since you looked the rear output of the case, don't forget the front yoke series as well.
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Offline Jeffy

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Re: transfer case swap
« Reply #3 on: November 30, 2012, 04:35:50 PM »
You are wanting to install into what model Jeep, and which trans? Auto TJs have 23-spline output. If other than TJ with auto, as stated, spline count will be an issue. Another may be the floor in a YJ since the overall size (diameter) is larger than the normal 231. The shift linkage shouldn't be an issue connecting, but adjustment will be necessary. That's not a problem, just something you have to do. Next, like you stated, fixed yoke. However, Rocktracs are not yoked, they are flanged. You could get a yoke or keep the flange. Next, while getting the Rocktrac, look for the rear ds since it will bolt to the flange. You may have to change the yoke on the rear axle to mate to the yoke series of the stock TJ Rubicon tcase. Now, I'm assuming the Rocktrac you are looking for is from a TJ and not the JK. The JK is similar but alas another different case....lol.
Next, depending on your year Jeep model, the TJ Rocktrac has an electronic speedo sensor and not the regular mechanical speedo. Lastly, since you looked the rear output of the case, don't forget the front yoke series as well.

Before the TJ got the 241OR and the SYE conversions of the mod to late 90's, people were swapping NVG241's into 4.0L YJ's.

Spline count won't be the only problem.  There's a big bearing and small bearing output shaft as well as a long spline and medium, short spline and early and late cut gears.

IIRC, the OP has an AX-5.
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Offline neale_rs

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Re: transfer case swap
« Reply #4 on: November 30, 2012, 04:44:33 PM »
You might consider saving up for an Atlas 4.3:1 or better.  Then you can rev it up in low range and run in higher transmission gears without worrying about damaging the planetary gears in the 241OR.

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Offline sharpxmen

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Re: transfer case swap
« Reply #5 on: November 30, 2012, 06:41:15 PM »
the planetary gears in the Rubi 241 are gigantic, you'd be busting other things before those would give way.

aside of the spline count there's also a matter of sealing and input length, the 241 in YJ seals the transmission and the tailhousing in the AX5 is lot shallower than the one on NV3550 or NSG370, not sure about the auto (if there's enough room). In any case there is no 21 spline input for the Rubi t-case that i know of, so in that case you'd need to do a transmission swap as well.
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Offline sharpxmen

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Re: transfer case swap
« Reply #6 on: November 30, 2012, 11:54:31 PM »
the planetary gears in the Rubi 241 are gigantic, you'd be busting other things before those would give way.

aside of the spline count there's also a matter of sealing and input length, the 241 in YJ seals the transmission [...]

in the post above i meant to say the 231 in the YJ and not 241

here's a side by side 231 planetary and the 241OR so you can see the size difference

'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
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Offline Bounty Hunter

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Re: transfer case swap
« Reply #7 on: December 01, 2012, 03:51:00 PM »
Go with the 2lo and sye, you'll be money, time, and headache ahead.

Offline Bounty Hunter

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Re: transfer case swap
« Reply #8 on: December 01, 2012, 04:50:37 PM »
Sharp, do you know the differences in torque ratings between those two planetary gearsets.

I built a stout 231 for my YJ, to include a 6-gear planetary, wide chain kit, 2lo, and Super-Short SYE.  The 4banger isn't going to hurt it.

Offline sharpxmen

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Re: transfer case swap
« Reply #9 on: December 01, 2012, 06:56:14 PM »
Sharp, do you know the differences in torque ratings between those two planetary gearsets.

I built a stout 231 for my YJ, to include a 6-gear planetary, wide chain kit, 2lo, and Super-Short SYE.  The 4banger isn't going to hurt it.

my point was that you won't damage the gears in the rubi, the post was in reply to this
You might consider saving up for an Atlas 4.3:1 or better.  Then you can rev it up in low range and run in higher transmission gears without worrying about damaging the planetary gears in the 241OR.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

Offline Bounty Hunter

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Re: transfer case swap
« Reply #10 on: December 01, 2012, 08:01:34 PM »
Right. The Rubi case can handle high rpm's unlike the Tera-low kit.

My point was you can't judge strength by size.  Case in point, the 231 has a higher torque rating than the 242.

Offline sharpxmen

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Re: transfer case swap
« Reply #11 on: December 01, 2012, 08:14:12 PM »
Right. The Rubi case can handle high rpm's unlike the Tera-low kit.

My point was you can't judge strength by size.  Case in point, the 231 has a higher torque rating than the 242.

let me see if i get this right, so you're saying the planetary gears in the 231 withstand higher load than the 241OR? weird that they intalled in the rubi and not go with a 231 then.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

Offline aw12345

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Re: transfer case swap
« Reply #12 on: December 01, 2012, 09:58:09 PM »
What he is getting at is that he built a 231 case with a 6 gear planetary that was used in Dodges if I am not mistaken, Still not sure the torque rating is all that much higher, the 241 in a Rubi is plenty stout with it's 4:1 ratio, About the only time they seem to break is when the Front CV joint seizes, which kills 231's equally easily.
The only valid reason for a 241 case over a 231 case is the reliable 4:1 low range.
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Offline sharpxmen

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Re: transfer case swap
« Reply #13 on: December 02, 2012, 12:53:39 AM »
What he is getting at is that he built a 231 case with a 6 gear planetary that was used in Dodges if I am not mistaken, Still not sure the torque rating is all that much higher, the 241 in a Rubi is plenty stout with it's 4:1 ratio, About the only time they seem to break is when the Front CV joint seizes, which kills 231's equally easily.
The only valid reason for a 241 case over a 231 case is the reliable 4:1 low range.


i wasn't suggesting he should go for the 241OR Rock-Trac (the OP), i answered a different post
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end

Offline Bounty Hunter

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Re: transfer case swap
« Reply #14 on: December 02, 2012, 02:58:10 AM »
let me see if i get this right, so you're saying the planetary gears in the 231 withstand higher load than the 241OR? weird that they intalled in the rubi and not go with a 231 then.
Not sure where you got that, I never claimed to know the torque rating of the 241or.  My point was size doesn't always matter lol.