[Preppi12]

I've got a 241j (rocktrac) case here I was hoping to swap into my zj. I've done a number of case swaps and breakdowns in the past but this one is different.

I've search quite a bit and have found a few doing this swap but they were all behind 4.0's or behind 5.2's in newer zj's (all 98's I think). Thus b/c they all required the medium length input shaft that the 241 already has. None had done input shaft swaps.

The planetary in these are completely different but that still didn't 100% mean that the input shafts couldn't be swaped. This is the best breakdown of the case that I could find.

http://www.jbconversions.com/pages/reviews/showpage.php?m=4wor&i=2002.12&p=3

Called jb converstions to ask them a question and they were very helpfull but told me that I'm pretty much f'd as I can't swap the long input shaft from my current 242 (which originally came from a 249) into this 241. So is swaping trans my only option here or has only come up with something different than what jb's said?

 

[Preppi12]

so whats the problem?? I mocked up my 241 onto my 93 ax-15 and it fit fine. My old 231 had the same lenght input as the 241....

That's the problem...my 241 doesn't have the same input shaft length. I need the long shaft and the 241 has the medium shaft. JB Conversions said they couldn't be swapped. I called them to ask b/c I new the planetaries were completely different.

 

[Preppi12]

How much spline enguagement would you get with the medium shaft? If it's just a matter of sealing on the output seal you may be able to use a spacer.

Which transmission do you have?

I need to pull the case again to find out how much engagement I'll have. I kind of feel like the dc wanted the shafts to mate up how they are and I'm concerned that not having enough that I'll twist the output shaft from the trans or worse break it and possibly f up the input shaft on the 241.

I doubt it would engage enough to reach the seal and I've heard about the spacers but know nothing more than it just keeps pressure on the seal if that's correct. More info? Where to get?

Excuse my ignorence but I'm not 100% sure on which trans I have...its either a 42re or 44re. How would I identify it? It was stock in my 94 w/ 318.

 

[Preppi12]

Basically you need spline engagement = to the width of the shaft for strength.

That's what I was told by jb conversions. I trust him b/c thats what they do but if I'm loosing...say .5" of shaft engagement...how much weaker is that going to make it?

 

[Preppi12]

If you mean 1/2" under the diameter of the shaft, I sure wouldn't do it - that's a large percentage of the diameter. Not worth the potential damage.

No, I ment loosing a half inch of engagement meaning if I used to have 2" of engagement and now I only have 1.5" of engagement...both being larger than the output shaft on the trans. Whats the potential of twisting/breaking the shaft over the stock engagement? And none of those numbers are factual...just example purposes.

Somehow that post just didn't sound right!...haha

 

[Preppi12]

If your goin to the extent of the swap, mite as well do it right.

Which is the whole reason why I'm asking these questions. If I didn't give a shit...it'd already be in!

Running the shorter input was suggested by two other parties...not myself but if it keeps getting recommended and there's nothing wrong with it than so be it. But again...back to my original statement in this post.

 

[Preppi12]

As long as the engagement is equal to or greater than the shaft diameter you are fine. There's little strength to be gained beyond that.

Cool thanks. I'll pull the case and measure the shaft and engagement amount and see what I've got. Can you give me some more info about the sleeve I would need for the seal if the shaft engagement does meaure out to be ok? And where to get it?

I am really shocked that this case has been out for 5 years and no mods are done to them. I was for sure that through searching/asking questions that someone had done some internal work and swapped some parts to improve the case or just to make it work for their application.

 

[Preppi12]

As far as the sleeve goes, you wouldn need to get yourself a 231/241/242 input shaft to cut up and cut off what you need.

As far as the mods for the tcase, it already fits YJ/TJ and most XJ's. I'm guessing there hasn't been a lot of call to swap them into ZJ's.

Good idea...I already have a spare input shaft here I could cut up. And I've seen them going into a couple things but always behind 6's minus the 2 I found which were 98 grands (5.9l) which had a different trans than I so input shaft lengths weren't issues. I'll pull the case next week/weekend and see what I've got in reguards to shaft ingagement.

Thanks...your input was helpful.

 

[Preppi12]

So I pulled my 242 out and took a few measurements. Looks like I have about a 1/16 of an inch more engagement than the shaft diameter. So it seems I'm just at what's required in engagement.

My next problem is that the end of the 241 input shaft falls dead center of the trans seal so even if I do add the sleeve that was recommended...I'm not sure how much its going to help. I feel like its going to leak. Granted I could lay a bead of rtv around the front of the case to prevent it but I don't feel like that's the right option. What are you thoughts?

 

[Preppi12]

suggestions anyone?

 

[Preppi12]

or cut down the trans to tcase adapter and reweld 1/2in lower

Thanks for the advice Bradford. Not sure if I fully understand what you mean here though.