The 2drx4 build, a Cherokee.

[2drx4]

Oh, BTW, please share what you find out about this. I want to adapt a NV242J to my 700R4 for the YJ - basically doing the inverse. If it is just a matter of swapping input gears then let's talk. I'd rather come up with something homebrew instead of paying $500+ dollars for some adapter.

My gut says it's not possible but you never know.

Well, what I gathered before doing a dry fit (will do later today) is that the input splines are the same (dodge 47RH is 23 output), but the depth is wrong. An AW4 output shaft extends about .5" past the back of the case, the dodge is flush. I think I can make it work with the input gear I have, but I might need to buy a D300 clocking ring - which is okay I need to clock the case anyways. Failing that, I'll need to swap the input, which might be a bit harder (the NP231 input might go in it, well, should).

 

[WFTW]

This is a GREAT thread! Can't believe I missed this before. What sort of time frame are you looking at for having it completed?

 

[Root Moose]

Ahh, gotcha. I'm dealing with 27 splines so I'm kind screwed that way. I have an NV242AMG here as well but the input to that is 32 splines so no joy.

Clocking the case sounds like the perfect solution to getting that extra .5". Make sure that you check that the spline profile/shape matches. You may have to change the input gear to get a matching involute. Chryco changed the involute shape some time around 1996-1997 - at least in the Jeep stuff. I reckon that if your AW4 and transfer case are around the same vintage they should match

I wanted to clock the NV242 in my XJ but ended up spacing the case upwards ~5/8" instead because I don't really have the time to mess around with dismouting the case and tail shaft housing to redrill it. Such is life.

 

[2drx4]

Ahh, gotcha. I'm dealing with 27 splines so I'm kind screwed that way. I have an NV242AMG here as well but the input to that is 32 splines so no joy.

I think most of the inputs swap anyways... As long as the case is of basically the same vintage and has the same low range (2.72:1, etc) then the planetaries are the same, and the input gear has the same cut. Beyond that, it's just a matter of changing them out. I'm making some ASSumptions here, but I know you can take the planets/carrier out of my 241 (6-planet setup) and swap them into a NP231 if you wanted. From that, one could ASSume that the inputs have to be basically the same.

Only one way to find out though.

 

[2drx4]

Test fit of NP241 to AW4:

The gap is about .500", using my calibrated eyeball. I'll give myself a +/-.250" tolerance on that. Anyways, obviously the long input on the 241 is bottoming on the output of the AW4. I have a couple options. I can cut the input down - it is splined as deep as a short input so there is no need for the extra engagement. I could potentially swap the 23 spline NP231 input in - I don't know if I can but I suspect I can. Or I can just buy a clocking plate for a D300 that is .750" thick, and get a couple birds stoned at once. Probably going to go that route - I know Novak makes one but it includes some useless seals and jazz. Advance might have one for atlas applications, I will have to look into that.

NP231 tail-housing on NP241 chain-case:

So, the bolt holes don't line up. Darn. It could be redrilled, but it wouldn't be ideal. However, on the contrary to what I thought, the NP241 chaincase is no wider/deeper than the NP231. That was measured by eye, again, as I left my calipers in PG. So, my NP231 SYE mainshaft should work, but I will need a NP241 SYE tail-housing.

NP241 vs NP231 tail-housing:

No point in this picture, but it shows the different patterns and you can sorta tell the rear bearing is larger on the NP241.


So, yeah, didn't do a lot today but I needed to try that.

 

[2drx4]

I think this is what I need.

http://advanceadapters.com/product/3721/(P/N-AS-8603)-Atlas-Transfer-Case-3/4"-Install-Spacer.html

 

[Root Moose]

Which version of the 241 is that? Dodge or GM? Did any of the Dodge transmissions use 27 spline output shafts?

 

[2drx4]

Which version of the 241 is that? Dodge or GM? Did any of the Dodge transmissions use 27 spline output shafts?

It's a dodge. Out of a 94 3/4 ton with a cummins and 47RH auto. Autos were 23 spline in that era, and I think the 5-speeds (NV4500) are 32. Could be totally wrong on that. You might try looking on Novak, read their tech on transmissions and look for anything with a 27 spline output and see where you can go from there.

Otherwise, I dunno... I had trouble finding info for this swap. Apparently there is a lot of confusion around what should be somple enough, and I don't think companies like Novak and AA are always as helpful as they could be as they are trying to sell a product.

 

[proto]

Here's an interesting datapoint to throw into your swap-info file:
Dodge made an NP241 with a yoke bolted directly on the rear output -- no SYE needed. Circa 1988 or so. I'd love to use one myself, but I'm running a 700R4, so not a plug-n-play swap for me.

Both the units I've seen were passenger-side drop. And, from photos, it looks like the tail housing is slightly different yet again. (I'll try to attach a photo.) Still, an industrious fellow might be able to find a donor t-case, swap some parts around and save the cost of a 'boutique' SYE.

 

[2drx4]

Here's an interesting datapoint to throw into your swap-info file:
Dodge made an NP241 with a yoke bolted directly on the rear output -- no SYE needed. Circa 1988 or so. I'd love to use one myself, but I'm running a 700R4, so not a plug-n-play swap for me.

Both the units I've seen were passenger-side drop. And, from photos, it looks like the tail housing is slightly different yet again. (I'll try to attach a photo.) Still, an industrious fellow might be able to find a donor t-case, swap some parts around and save the cost of a 'boutique' SYE.

View attachment 25922

Wow. I didn't know that. But suddenly things make even more sense. I knew that the first HD SYEs for NP231s were made using NP241 mainshafts. That is where those mainshafts would be from. I had assumed they were cutting down and tapping the slip-yoke style mainshafts. Apparently I was wrong.

But, it doesn't look like I have anything to gain from finding one of those cases... I doubt I could modify that tail-housing to work.

I have a plan to make my own SYE if needs be... Using the slip-yoke shaft and the 241 tail-housing. Providing I can find the correct yoke.

 

[Root Moose]

The SYE on the Dodge case is transferable to the GM version, and I'd guess any non Jeep version of the NV241.

There is a thread on the PBB that discusses it; sorry, don't have the link handy.

That said, I think I'd rather run the JB Conversions super short SYE. For the ~$350 of that aftermarket part versus the screwing around in the junk yard and spending time/money at it I think it is a valid alternative.

 

[2drx4]

The SYE on the Dodge case is transferable to the GM version, and I'd guess any non Jeep version of the NV241.

There is a thread on the PBB that discusses it; sorry, don't have the link handy.

That said, I think I'd rather run the JB Conversions super short SYE. For the ~$350 of that aftermarket part versus the screwing around in the junk yard and spending time/money at it I think it is a valid alternative.

It's probably transferrable between the passenger side drop ones... The shift rail won't line up, from the looks of things.

The super-short SYE might be a viable option. I am going to wait until I get the driveline mocked up before I commit to anything. I want to run 1350 CVs, if the flange to do so is readily avaliable for the rear. I'd also like the driveshafts to be the same length, or very close to it, if possible.

 

[proto]

. . . I think I'd rather run the JB Conversions super short SYE. For the ~$350 of that aftermarket part versus the screwing around in the junk yard . . . .

Oh sure, take the easy way out. ;-)

Actually, I was hoping someone would tell me I can keep my GM tail housing and just swap in the Dodge shaft and seal.

I did do a search on Pirate for this a while back, read through a couple dozen threads -- but all I got were some oblique references. Didn't really find a good thread on the subject. If you happen across a bookmark in your files, please post it up! TIA

 

[2drx4]

Kinda a dismal update. Camera ran out of batteries on me...

Cut the two frame rails for the belly section to length. Then I drilled some big ol' holes in them and welded in some tube as sleeves. Yay.

Then I squared 'em up and tacked them in. Wait, I build that rear link x-member first. Okay, whatever. Stuff got done, it doesn't really matter how.

And I tacked it my other braces... Oh, the 2x2 peice running retardedly through the whole thing and sticking out both sides, the one with the angle finder, yeah, it's only a temporary brace. I'd leave it but it would interfere with my transmission placement, I think.

Anyways... The rear section is now kicking my MMM. Apparently there isn't anything solid that I can weld to back there anymore. So, I'll have to address that. Luckily I have a half decent plan. Or what I think is a half decent plan.

 

[Root Moose]

Oh, the 2x2 peice running retardedly through the whole thing and sticking out both sides, the one with the angle finder, yeah, it's only a temporary brace. I'd leave it but it would interfere with my transmission placement, I think.

LOL Ya think? ;D

You do realize that this build is getting more an more nuts everytime you post, eh?

Don't stop - this is awesome! I can't wait to see what it looks like skinned.