pug Posted March 28, 2009 Share Posted March 28, 2009 What is the differance between a 2.5 and 4.0 transfercase. Besides 21 and 23 splines and can you change it over. thanks Link to comment Share on other sites More sharing options...
ren Posted March 28, 2009 Share Posted March 28, 2009 The early 2.5 motors normally had a NP 207, which is good, but some of the parts can be hard to find for it. The 4.0 is normally found (except for the really early, like 1987 model) with the NP 231 or 242 X-case. The biggest thing to watch for when swapping the X-cases is the length of the input shaft, and how far it sticks out. This can vary from tranny to tranny, i.e.: just because it was behind a manual tranny, does not guarantee that it will fit properly to your manual tranny. Now, you can swap the input shafts for the one that you need, but again, you have to watch, as the angle that the gears was machined at was also changed periodically. Link to comment Share on other sites More sharing options...
LEAD_NOT_FOLLOW Posted March 28, 2009 Share Posted March 28, 2009 21 and 23 spline has nothing to do with 4cyl vs. 6cyl. It has to do with the year. Mid 1990 was the change over year to the larger spline. Link to comment Share on other sites More sharing options...
ren Posted March 28, 2009 Share Posted March 28, 2009 Ok, I left out the part about the auto tranny spline counts. IF the 4cyl. motor has the 3 speed auto, then it is a 23 spline, as the Mopar Torqueflite series NEVER used a 21 spline output. EVER. Now, if the 4 cyl. has the 4sp auto, it can go either way, depending on the year of manufacture. On the manaul trannies, I know that the 4.0 changed in mid 90 to the 23 spline form the 21, as I had a 90 XJ 2 door that was built with the 21 spline AX-15, which was apperently only around for afew months for some reason. I found out about this the fun way, when I had to rebuild the X-case, and the new gear set was the wrong spline count. :grrrr: Link to comment Share on other sites More sharing options...
pug Posted March 28, 2009 Author Share Posted March 28, 2009 To be safe just get same year transfercase as transmission or did they change in middle of year. Also what is the differance in transfercase shifters 1990 and 1998. One is from a 207 mj and the other one will be from a wrangler. Link to comment Share on other sites More sharing options...
Geonovast Posted March 29, 2009 Share Posted March 29, 2009 Any 4 cyl with a 3 speed auto should be an 86 IIRC, and would have the NP 207. I may be wrong on that, however. Link to comment Share on other sites More sharing options...
ren Posted March 29, 2009 Share Posted March 29, 2009 Yep, and remember that the 84-86 Cherokee was available like that, too. Link to comment Share on other sites More sharing options...
pug Posted March 30, 2009 Author Share Posted March 30, 2009 So what is a average price for a 231. The cheapest i can find is $600.00 for a 1998 in missouri. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted March 30, 2009 Share Posted March 30, 2009 21 and 23 spline has nothing to do with 4cyl vs. 6cyl. It has to do with the year. Mid 1990 was the change over year to the larger spline. absolutely false 4 cyl ax5's remained 21 spline until at least 1996, and probably until 2001. the changeover year was 1990 for 4.0 equipped vehicles. so yes, 21 vs 23 spline does have something to do with 4cyl vs. 4.0 differences. anyways, all the OP needs to know is that he needs an np231 or np242 behind a 4.0, with matching spline count to his transmission. likewise with a 4 cylinder. be aware of spline count and choose your transmission accordingly. I personally would upgrade at least to a 231 with a 4 cylinder...207's are grenades waiting to go off if they're abused. Link to comment Share on other sites More sharing options...
xjblue Posted March 30, 2009 Share Posted March 30, 2009 A helpful chart for input gear spline count and length changes. http://www.novak-adapt.com/knowledge/np ... _gears.htm Link to comment Share on other sites More sharing options...
Geonovast Posted March 30, 2009 Share Posted March 30, 2009 What case are you looking for? I have a 231 from an 88 XJ 4.0 BA 10/5 21 spline short input I may be willing to part with. Link to comment Share on other sites More sharing options...
Pete M Posted March 30, 2009 Share Posted March 30, 2009 So what is a average price for a 231. The cheapest i can find is $600.00 for a 1998 in missouri. Try car-part.com It's a search engine for lots of junkyards I paid $50 for my last one. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted March 30, 2009 Share Posted March 30, 2009 I just sold one local for $150 23 spline and that was $100 under priced Link to comment Share on other sites More sharing options...
pug Posted March 30, 2009 Author Share Posted March 30, 2009 I did try car-part they were from $550. on up. I need a 21 spline for a 1998 ax5 if that matters. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted March 30, 2009 Share Posted March 30, 2009 I did try car-part they were from $550. on up. I need a 21 spline for a 1998 ax5 if that matters. I have one from a 1994 which would probably work, but shipping is gonna be expensive. Link to comment Share on other sites More sharing options...
Pete M Posted March 31, 2009 Share Posted March 31, 2009 I did try car-part they were from $550. on up. I need a 21 spline for a 1998 ax5 if that matters. Where are you? and what parameters are you searching under? Link to comment Share on other sites More sharing options...
pug Posted March 31, 2009 Author Share Posted March 31, 2009 I am in Arnold Mo (st.louis) I just went on novac conversion web site it said Anything newer than 1994 the input shaft is 14 spline and the stick out lenght is 7 1/2. Is that becaus it is a external slave cylinder. Link to comment Share on other sites More sharing options...
Geonovast Posted March 31, 2009 Share Posted March 31, 2009 That would be for the transmission input shaft. The 14 spline is for the clutch disk. Would a 98 AX-5 be a 21 or 23 spline? Link to comment Share on other sites More sharing options...
pug Posted March 31, 2009 Author Share Posted March 31, 2009 So will pre 1995 transfercase work then. I also herd something about front bearing cover on the transmission has to be replaced. Has anyone herd of this. Link to comment Share on other sites More sharing options...
Geonovast Posted March 31, 2009 Share Posted March 31, 2009 That has nothing to do with the transfercase. That's for the clutch assembly, on the front of the transmission, between the trans and the motor. If you're keeping your original transmission, you don't have to worry about any of that. But yes, the front bearing retainer on internal and external slaves is different. Externals stretch out to cover most of the transmission input shaft. internals are pretty much flush with the retainer plate. Ignore the toyota one and the early/late above them, as usual the people on JO don't know what they're talking about. Left is internal setup, middle is external. This is what you need to worry about for spline count.(pic is actually an AX-15, but close enough) Link to comment Share on other sites More sharing options...
Pete M Posted March 31, 2009 Share Posted March 31, 2009 So will pre 1995 transfercase work then. I also herd something about front bearing cover on the transmission has to be replaced. Has anyone herd of this. Is there something wrong with yours? or are you doing a 4wd conversion? Link to comment Share on other sites More sharing options...
pug Posted March 31, 2009 Author Share Posted March 31, 2009 I am doing 4x4 conversion and i want to keep the external slave cylinder. I guess my question is what year transfercase will work on a 1998 ax5. thanks Link to comment Share on other sites More sharing options...
JeepcoMJ Posted March 31, 2009 Share Posted March 31, 2009 I am doing 4x4 conversion and i want to keep the external slave cylinder. I guess my question is what year transfercase will work on a 1998 ax5. thanks umm. I hope you are planning on swapping the transmission to a 4wd trans as well... the 2wd transmission is NOT compatible with the 4wd parts...the output housing is different, and the output shaft is not only shorter but a different spline count. so, if you're doing a swap it is necessary to swap to 4wd. Link to comment Share on other sites More sharing options...
pug Posted March 31, 2009 Author Share Posted March 31, 2009 Yes it is a 1998 4x4 transmission. I just need to know what transfercase and year i need Link to comment Share on other sites More sharing options...
JeepcoMJ Posted March 31, 2009 Share Posted March 31, 2009 Yes it is a 1998 4x4 transmission. I just need to know what transfercase and year i need ok, what year is it going in? any ax5 t-case will work. they almost all used long snouts input shaft through around 1988 or so when they changed to an np231. any 21 spline np231 should work for you. it should have a rear output housing set up for a short snout input np231, but you can put a long snout input np231 in them since the space is there. between geonovast and I we're the ones on the club who have messed with ax5's the most...both of us have successfully converted a 2wd ax5 to 4wd ax5 transmission by swapping gears on tail shafts etc. I've seen the most difference in rear output housings, varying from short to long input housings. anywho, you should be all set with a short input np231. if you find one with a long input you'd also be fine. Link to comment Share on other sites More sharing options...
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