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NP242 behind a AX-15

T

terryd

NAXJA Forum User
Location
Elk Creek/Covington Va
I was wondering how much trouble it is to put a NP242 behind a AX-15? My NP231 is pretty haggard and I've gotten used to Julie's WJ with the NP242. It's more or less a camping/family/DD rig, so I don't think strength will be an issue.

Will I need to change cross members, front drive shafts (going to go SYE and new rear shaft either way), or anything major? Thanks for any advice!

Oh, and would 2wd Low be more or less useful than AWD?
 
im not familiar with the 242 behind the AX-15 at all. but ive got some questions you may want to answer first...

what lift height are you at? you say you want to do a SYE, i thought the advantage of the 231 over the 242 was the aftermarket support. as there is nothing in the form of a SYE for the 242. correct me if im wrong, but thats what i had read years ago. all of my XJs have had 231s. so that may be a turn off for the 242 unless you want to do the hack and tap method.

i beleive the crossmember mounts to the transmission, not the transfer case behind it. so you would not need to change anything there.

as for 2low vs AWD, i cannot say... i have not driven either. though 2low sounds FUN.
 
I wouldn't mind the hack-n-tap on a NP242. I've read where several people have used it without any problems. I'm only on ~3" of lift, but the last time I built new bastard packs for it, it vibed a little till the springs dropped some. I'm wanting to go with a set of OME Heavy 2" springs (I have a 1.5 or 1.75" RE shackle in there now) in the rear so I can pull a trailer.

As for 2Low, I definitely see some advantages, especially pulling a trailer. However, AWD works amazing in the snow as I've witnessed with Julie's WJ and at the moment, I'm driving 3hr's away from home to get to work. Hopefully that will change soon, but I'll still be close to 30min away at highway speeds.

For the NP231, the SYE, rebuild kit with chain, and 2Low kit are going to be ~$700. I've had a fellow member here offer me a good-working NP242 for $150 and my worn out NP231.
 
I loved my last XJ with a np242, Id say break new ground and do it. I believe the DS should be the same, just the overall case of the np242 is bigger due to the "diff" or wizard in there so the 231 skid plate might not work without alittle modification.
 
I believe you'll have to modify/adapt/replace the tcase shifter linkage - but it should not be a problem apart from that. I've got a 242 I'm planning on sticking behind the AX-15 going into my 88 (unless I get really lucky and score a D300 - and possibly an NV3550.)

I'll either just make a new shifter linkage (using threaded rod and probably ball socket ends between the bellcranks) or just get the kit from Novak - I like the look of it, and I've heard it works well.

The transfer case only really mounts to the transmission case - and all "modern" NP/NVG transfer cases use the same mounting pattern (which is on the D300 anyhow. At least, the D300 unless it was used by IHC in the Scout.)
 
VAhasnoWAVES said:
what lift height are you at? you say you want to do a SYE, i thought the advantage of the 231 over the 242 was the aftermarket support. as there is nothing in the form of a SYE for the 242. correct me if im wrong, but thats what i had read years ago. all of my XJs have had 231s. so that may be a turn off for the 242 unless you want to do the hack and tap method.
Click to expand...
The H&T is an SYE, it is just not a heavy duty shaft replacement like the ones sold by aftermarket companies such as AA and Teraflex. With that said, there is NOTHING wrong with a H&T kit. I've had one on the back of my 242 for 5 years without any problems, it even outlasted the transfercase.

terryd said:
I wouldn't mind the hack-n-tap on a NP242. I've read where several people have used it without any problems. I'm only on ~3" of lift, but the last time I built new bastard packs for it, it vibed a little till the springs dropped some. I'm wanting to go with a set of OME Heavy 2" springs (I have a 1.5 or 1.75" RE shackle in there now) in the rear so I can pull a trailer.
Click to expand...
Yep, I've had no problems with the H&T. Its a fine kit, a lot of people just don't like it because of the name, and the fact that it doesn't replace the output shaft, without ever have running a H&T.
 
A few here have done it, if I remember right the rear ds needs to be 1" shorter but with a lift you may already be there. I like my wifes ZJ with the 242, great in snow for going but like all automatics not so great for slowing down. The AX/242 are my idea of an ideal combo.
 
I asked this same question a while ago I think (or at least I posted in another thread on the topic since I was considering the same swap).

IIRC I was told that there is a bit of 'slack' in a NP242 due to the clutches or something, I forget the details. It was mentioned that driving with this in a 5-speed would be more noticeable and possibly put more stress on the case when shifting between gears than an automatic trans would, which could explain why the 242 wasn't available behind any of the manual trans XJs.

I am trying to look up the thread I posted in a while back, if I can find the post I will link to it. I was going to try and pick up another 5-speed XJ for a (stock) DD and was thinking about swapping a 242 in but I feel like I got talked out of it. Though lately I have been driving with a Detroit out back in my current XJ which has plenty of 'slack' so I am getting used to driving with it... but still, the t-case may behave differently and not play nice.
 
VAhasnoWAVES said:
as there is nothing in the form of a SYE for the 242. correct me if im wrong,
Click to expand...
Tom Wood sells a SYE for the 242. New tail cone and cut shaft. Not a true hack and tap as he cuts and taps the shaft for you.
themangeraaad said:
IIRC I was told that there is a bit of 'slack' in a NP242 due to the clutches or something, I forget the details. It was mentioned that driving with this in a 5-speed would be more noticeable and possibly put more stress on the case when shifting between gears than an automatic trans would, which could explain why the 242 wasn't available behind any of the manual trans XJs.
Click to expand...
The 242 doesn't use clutches. Think of the 4 full time as an open diff. But, yes, I heard the same thing about the "slack" as you did. But i have heard of two swaps that were done with the 242 and manual and no mention of any problems.
 
Talyn said:
The 242 doesn't use clutches. Think of the 4 full time as an open diff. But, yes, I heard the same thing about the "slack" as you did. But i have heard of two swaps that were done with the 242 and manual and no mention of any problems.
Click to expand...

That's why I said clutches or something. I knew there was no clutch but I couldnt make my brain function too well this morning to explain otherwise.:laugh3: Damn lack of sleep... or maybe it's just me :gee:
 
Good info guys! Thanks alot! Now another question...

Will running a locking hub conversion hurt the NP242? The pump is still driven off the input shaft, correct? I may or may not do the hub conversion, but I'd like to have the replaceable bearings.
 
MJ79.jpg

MJ83.jpg


It will boltup just fine, in case there was any question.
 
terryd said:
Good info guys! Thanks alot! Now another question...

Will running a locking hub conversion hurt the NP242? The pump is still driven off the input shaft, correct? I may or may not do the hub conversion, but I'd like to have the replaceable bearings.
Click to expand...

Like the Warn hub conversion kit?

Nope, I have a HP44 in front with manual hubs and a 242. (which will be replaced by a 241 next weekend), and I usually drive around with the hubs unlocked.
 
It bolted right up for me, I haven't had any problems with mine. I made my own shifter linkage as I was also converting to a 4x4 at the time, also I have a disko d30 with a posi lock, so I have 4 Fulltime and 2low! found the posi lock in the junkyard for $15 during cash for clunkers :D
 
Awesome! I found the Tom Woods DS/SYE combo for the NP242. I'm going to go that route. I think for DDing and the mild kinda wheeling I'm interested in doing in it, it'll be the ideal case.


Now, is there anyway to get AWD Low out of it? lol :greensmok
 
One other thing, does the slip yoke CV work any better than what's in there factory? I know it's not as desirable as using a SYE, but for the limited use offroading this XJ will see, is there any reason for me to spend the extra money to get a full SYE instead?
 
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