Anybody got a NP231J from a YJ laying around that they would like to sell

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MoparMan

MoparMan

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Hayden, AL
I'm looking for a whole complete NP231J from a YJ. One from a TJ might work work too. My YJ is a 4 cyl 5-speed. After my front driveshaft come out a while back and knocked a hole in mine, I got a 231 from an AMC and it's not working out.

Or does anybody know someone thst could weld up the hole in my original case?

I'm located in Hayden, AL
 
Do you have any pics of the damage?

I have one, but it has the Tera-low 4:1 kit in it. So the front half is different, which is probably the side you need. The planetary gears are messed up in it, those tera-low kits just didn't hold up to hard use. It still has some salvageable parts in it though, like the sye and it has a 2w low selector in it.
Also it is a 27 spline input. Yours may be a 23 seeing how it is behind a 4cyl, I'm not real sure about that though. Either way I may can help with damage too.
 
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Yes, the damage is in the front half. And yes, mine is a 23 spline input. I'm pretty sure my planetary gear is still good. Would it work with the parts you've got?
15942963557038397602789752440966.jpg
 
Smalls said:
Do you have any pics of the damage?

I have one, but it has the Tera-low 4:1 kit in it. So the front half is different, which is probably the side you need. The planetary gears are messed up in it, those tera-low kits just didn't hold up to hard use. It still has some salvageable parts in it though, like the sye and it has a 2w low selector in it.
Also it is a 27 spline input. Yours may be a 23 seeing how it is behind a 4cyl, I'm not real sure about that though. Either way I may can help with damage too.
Click to expand...

Would my 23 spline input/planetary gears work with what you've got? Where are you located?
 
I live close to Stoney.
The housing won't work, the half you need anyway. Everything else would work. I've repaired some aluminum oil pans that had holes knocked in them and they turned out ok. I could try to fix that one if you want me to.
 
It is rare to have the 23 spline on the 2.5. Most of those I have came across were 21 spline. Is that why the AMC case isn't working out?
 
Smalls said:
I live close to Stoney.
The housing won't work, the half you need anyway. Everything else would work. I've repaired some aluminum oil pans that had holes knocked in them and they turned out ok. I could try to fix that one if you want me to.
Click to expand...

Ok, sounds good. Send me a pm with a phone number and good time to call or text you. Thanks
 
muddinmetal said:
It is rare to have the 23 spline on the 2.5. Most of those I have came across were 21 spline. Is that why the AMC case isn't working out?
Click to expand...

Nah, that's not the issue. I put all of my parts into the AMC case. It worked for a little while, but then started to act up.
 
MoparMan said:
Nah, that's not the issue. I put all of my parts into the AMC case. It worked for a little while, but then started to act up.
Click to expand...
I'd dig deeper into what's acting up. Bent shift fork, shift pads, linkage out of adjustment, stretched chain. Those are all incredibly common issues wit 231's. But they are very easy/cheap fixes.
 
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The Luke said:
I'd dig deeper into what's acting up. Bent shift fork, shift pads, linkage out of adjustment, stretched chain. Those are all incredibly common issues wit 231's. But they are very easy/cheap fixes.
Click to expand...
Yeah, I've already taken it apart 4 times looking for the problem. I can't figure it out, so my next step is to take it to a professional for them to lool at it. Just thought I would see if I could find another case that was in working order.
 
The really weird part is, it will work fine in 4 lo. But in 2 hi and 4 hi it's like it kicks in and out of gear.
 
You probably know this, but depending on how modified the jeep is, like it has a body lift, linkage out of adjustment could cause that. Trans and motor mounts too. If you have taken it apart then you probably know what to look for inside, like the pads on the shift and mode forks.
 
Smalls said:
You probably know this, but depending on how modified the jeep is, like it has a body lift, linkage out of adjustment could cause that. Trans and motor mounts too. If you have taken it apart then you probably know what to look for inside, like the pads on the shift and mode forks.
Click to expand...
Yeah, the linkage is definitely not out of adjustment. It very well could be a shift fork though. The pads are all fine, but it could be bent just slightly enough for me to not notice.
 
Disconnect the linkage, shift it by hand and see if it still does it. That'll eliminate one thing.

It's been a minute since I've been in a 231. But, if i remember right, you can actually install one of the shift forks backwards and it'll do what you're describing.
 
The Luke said:
It's been a minute since I've been in a 231. But, if i remember right, you can actually install one of the shift forks backwards and it'll do what you're describing.
Click to expand...
I thought about that, and maybe it is upside down. Wierd thing is, when it's not installed into the Jeep and it's just laying in the floor it works perfectly.
 
MoparMan said:
I thought about that, and maybe it is upside down. Wierd thing is, when it's not installed into the Jeep and it's just laying in the floor it works perfectly.
Click to expand...
Yea, you apply some actual torque to it and if it’s not full seating the shift ring it’ll pop out. I bet that fork is bent or not in correctly. There really isn’t anything in the physical case itself that’ll cause any issues as long as their isn’t a gaping hole in it.
 
The Luke said:
Yea, you apply some actual torque to it and if it’s not full seating the shift ring it’ll pop out. I bet that fork is bent or not in correctly. There really isn’t anything in the physical case itself that’ll cause any issues as long as their isn’t a gaping hole in it.
Click to expand...

Gotcha
 
Smalls said:
Do you have any pics of the damage?

I have one, but it has the Tera-low 4:1 kit in it. So the front half is different, which is probably the side you need. The planetary gears are messed up in it, those tera-low kits just didn't hold up to hard use. It still has some salvageable parts in it though, like the sye and it has a 2w low selector in it.
Also it is a 27 spline input. Yours may be a 23 seeing how it is behind a 4cyl, I'm not real sure about that though. Either way I may can help with damage too.
Click to expand...
I was mistaken. The tc I have is a 23 spline input.
 
So I picked up an extra 231J from Smalls yesterday. I'm gonna see if I can make 1 good case from the 3 I've got now lol. Big thanks to Smalls for the great deal!
 
MoparMan said:
So I picked up an extra 231J from Smalls yesterday. I'm gonna see if I can make 1 good case from the 3 I've got now lol. Big thanks to Smalls for the great deal!
Click to expand...
Bleepin Jeep has a few write ups on sye kits and hybrid cases that show exactly how they all go together and what to watch for. You might check them out
 
I pulled mine from my 2.5l 97 model TJ to swap entries for another 231 with the Teralow kit and a SYE added. First ride has been awesome! I left the old one at the garage in GA that did the swap for me. I could ask if he still has it.
 
majic2001 said:
I pulled mine from my 2.5l 97 model TJ to swap entries for another 231 with the Teralow kit and a SYE added. First ride has been awesome! I left the old one at the garage in GA that did the swap for me. I could ask if he still has it.
Click to expand...

Sounds good. I think I'm good, but if you could check on it just in case that would be great.
 
I finally figured it out, well at least I think I did, still gotta put it back together and get it in the Jeep. But I'm pretty positive this should fix it. The bearing that input/planetary gear rides on is thicker in my original case. So this whole time it was the planetary sliding back and forth and losing engagement.
0717201845.jpg
 
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