• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

NP242 to NP231 Swap Question

X

XJBill

NAXJA Forum User
Location
Erie, PA
Is going from a NP242 t-case to a NP231 t-case a "bolt on" thing to do. I want to get an AA HD SYE and it's not offered for a NP242. I had to use RE's "hack-n-tap" system on my 242. I have a 99 XJ and was wondering if the swap is a possibility without too much trouble. Will the driveshaft length be the same or do I need a new one? Will the same linkage work on both? Also, is there anything I should watch out for? Anybody done this? Any help would be appreciated.
 
XJBill said:
btt:
Click to expand...


Bill, the only thing you need to look out for is the input spline shaf count. Your 99 will more that likely have a 23 spline so you need a 231 with a 23 spline. They are readily available. I did it on my 92 with no problems. My 4wd light doesn't work anymore but I didn't really care. I'm pretty sure that someone makes a SYE for the 242, I just don't know who.
 
i installed a 231 from a 98 tj with a manuall trans into a 91 xj automatic. the input shaft on the 231 was too long for my automatic. i cut the input shaft on the 231 and now it all fits. my 4x4 light works normal. jack
 
Call Tom Woods for a SYE for a 242, that's where i got mine. No reason to swap t-cases just to get rid of the Hack 'n' Tap.
 
tom woods is a hack and tap, but he does it for you. you can only het a heavy duty main shaft kit for a 231. i know because my tom woods shaft broke. nothing wrong with tom woods kit. its just not heavy duty like a AA. jack
 
have you broken the stock output shaft?

if you're going to go to the expense of swapping t-cases, why go with another chain driven case?

I beat on my 242 (with 36's and fairly high gears, which puts lots of stress on the driveline)constantly and haven't broken an output shaft yet (broke two tailcones, and that was because of breaking driveshafts with the skinny pedal against the floor, going uphill)

I have stretched 3 chains, destroyed the center differential and cracked the case in half, but NEVER broke the output shaft.

IMO, the swap is not worth it.
 
Thanks for the info guys!

I havn't broken the tail shaft, I'm just having trouble with the rear seal leaking. When I did the RE SYE, I took the T-case apart and took the shaft to a buddy of mine who has a machine shop and he cut it and tapped it for me. Since I had the t-case apart, I figured I would replace the seals trying to PREVENT leaks. When I took it down to get it inspected, I noticed it had been leaking all over the driveshaft and splashing up on the floor boards. The seal had come apart. I originally had a hard time getting the right seal from the dealer cause they told me it could be one of 3 different NP242's. Didn't make sense at the time and still doesn't. It took a couple try's to get the right one. Also, there is a pressed on dust cover type part that got bent (of course) trying to get it off. It goes on the tailshaft and the boot that coveres the slip yoke splines hose clamp to that. The dealership I went to said they couldn't get it and that I didn't need it anyway. Well guess what, it appears I do. I'm getting all the right parts from another dealership that my mechanic friend recommended to me and it should be fixed sometime this week.
 
ok so i just went from a 242 to a 231, its all went well except for i cant figure out how to make my speedo wire work?. i got the terafelx extrashort sye and its had three prongs in the connector and my jeep only has two prongs on the connector? what should i do everything works except for my speedometer.
 
i have seen lots of 242 hack and taps and 9/10 its not the seal leaking, its the end of the flange thats leaking cause the oil slowly makes its way along the splines and out the end where the RE flange uses a snap ring and washer for the bolt to go through. The oil just gets around that washer and leaks...for some reason RE never realized that the front output uses a rubber star washer to prevent this, and have yet to include one for the rear.

mines doing it now even thou I used a crap load of silicone gasket maker to try to seal it. I am going to remove it and try again with a home made star washer or simply an oring.

I would check and see if thats the problem first.
 
For a 1999, there is one rear-output seal part number--4798117. They are probably thinking about the two different numbers that might be on the tag (52098899 and 52111083). The seal is the same for either. The leak could also be a bad oil slinger (p.n. 4798119).

I wouldn't replace a whole t-case just because of a leak, but if you have the time, money, and inclination go ahead.
 
XJBill said:
Is going from a NP242 t-case to a NP231 t-case a "bolt on" thing to do. I want to get an AA HD SYE and it's not offered for a NP242. I had to use RE's "hack-n-tap" system on my 242. I have a 99 XJ and was wondering if the swap is a possibility without too much trouble. Will the driveshaft length be the same or do I need a new one? Will the same linkage work on both? Also, is there anything I should watch out for? Anybody done this? Any help would be appreciated.
Click to expand...

Would you be interested in getting rid of the 242? If so, how much?

Can anyone tell me if his 99 242 will fit my 92 AW4?
 
XJBill said:
Thanks for the info guys!

I havn't broken the tail shaft, I'm just having trouble with the rear seal leaking. When I did the RE SYE, I took the T-case apart and took the shaft to a buddy of mine who has a machine shop and he cut it and tapped it for me. Since I had the t-case apart, I figured I would replace the seals trying to PREVENT leaks. When I took it down to get it inspected, I noticed it had been leaking all over the driveshaft and splashing up on the floor boards. The seal had come apart. I originally had a hard time getting the right seal from the dealer cause they told me it could be one of 3 different NP242's. Didn't make sense at the time and still doesn't. It took a couple try's to get the right one. Also, there is a pressed on dust cover type part that got bent (of course) trying to get it off. It goes on the tailshaft and the boot that coveres the slip yoke splines hose clamp to that. The dealership I went to said they couldn't get it and that I didn't need it anyway. Well guess what, it appears I do. I'm getting all the right parts from another dealership that my mechanic friend recommended to me and it should be fixed sometime this week.
Click to expand...

I broke a tailshaft. Lots of skinny pedal. Factory 3.55's with 33 mt claws.
 
You must log in or register to reply here.

Similar threads

L
Manual to Auto transmission swap
Replies
9
Views
199
lvcanyoneer1
L
D
97 XJ needing driveshaft specs
Replies
4
Views
3K
cherokeecrawler
C
D
AW-4 and 242 HD Rebuild Options?
Replies
12
Views
4K
RCP Phx
R
89Mock
Gauge Cluster Swap: Mechanical to electric speedometer
Replies
3
Views
3K
kastein
kastein
O
SYE vs Fixed Yoke spline geometry
Replies
7
Views
3K
RCP Phx
R
Back
Top