Drive shafts replacement, thoughts?

Rickyd said:
Looks like someone put a yj style shaft in. Hopefully it is still the stock yoke and the right double cardan shaft can go back in.

By the looks of that tcase it needs torn down and new seals. Probably new bearings too.

Does the tag on the back say np231j ?
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Looks like it just say 231J, I have attached a photo of it too. Also, not sure about the YJ axle, I had no problems with it when in 4wd, just joint going out.. Because I have it down and out of the way I also am going to put in a cable shifter for the 4wd, right now it won’t shift into 4low, due to body lift. Please let me know what you think

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I agree with Rickyd, it looks like you have a YJ-style single cardan front driveshaft, which could be responsible for vibes and noise. YJs could get away with it because of their front-axle disconnect system which kept the front driveshaft from spinning in 2wd. TJs don't have the axle disconnect so their front shafts are always spinning when the vehicle is in motion. Which is why they have double-cardan front shafts.

I would pull the front shaft for now and ultimately replace it with a double-cardan shaft.
 
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rouxbicon said:
I agree with Rickyd, it looks like you have a YJ-style single cardan front driveshaft, which could be responsible for vibes and noise. YJs could get away with it because of their front-axle disconnect system which kept the front driveshaft from spinning in 2wd. TJs don't have the axle disconnect so their front shafts are always spinning when the vehicle is in motion. Which is why they have double-cardan front shafts.

I would pull the front shaft for now and ultimately replace it with a double-cardan shaft.
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I have it pulled, I wonder how long it’s been in there I’ve owned for almost 6 years now and I bought it from my wife’s old boss, he got in in about 2010-11. He didn’t do anything to it but literally drive it to work and home on fridays. So I know it’s been about 13 years and the only issue that I had develop was the rear ujoint was going out which was the reason I was pulling it.
 
Ok so the plot has thickened. After closer inspection i noticed that it would appear the front out put shaft of the t case is for a non cv yoke. It is my understanding that TJs had CV yokes. The only difference I can visibly see is the non cv yoke uses two “U” bolts that attach the drive shaft to the out put shaft of the T-case. So this maybe why it is not a TJ shaft and is a YJ shaft. I attached a picture that compares cv and non cv yoke or side by side. Please let me know if my theory is correct. If this is correct I wonder why someone swapped it out. I have read that the NP231J has been around since the late 80’s so maybe they had to swap the T case and it was an older one with a non cv yoke and rather then swapping to a cv yoke they just swapped out the drive shaft.

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The only difference in those pics is a u bolt placed through the holes.neither looks like your yoke

You'll need to dig deeper than that to know what yoke is on it or which tcase it has
 
Rickyd said:
The only difference in those pics is a u bolt placed through the holes.neither looks like your yoke

You'll need to dig deeper than that to know what yoke is on it or which tcase it has
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I’m not a mechanic but to me the non cv looks fairly close to mine, mine looks like it sticks out a little further then what the one in the photo I attached before this post. I have attached a photo of mine and the NP231J tag on the back of my T-Case. Please let me know how I would dig deeper to know what yoke I have? My knowledge of this stuff is limited, yes I can swop out parts but a lot of people can do that.

The tj drive shaft is not attached with the “U” style of bolts, right?

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Is it possible that the PO just decided to leave the double carban off? I may take the drive shaft to a local off road shop to see if they can determine what to do. Im shocked there is no ID number in the drive shaft.I’m tempted to purchase the double carbine joint to see if it will fit and bolt back up.
 
Ok, update. I went by the off road shop both the guys who have TJs, one of them has 3, must be nice. Anyway I asked about the double cardan and, they said a double cardan was not stock and when I showed a few pics of what I had one of the other guys said that he has the exact same setup as mine. With that info I stopped at the local Jeep dealership in Town, I know a guy who is big into TJ’s he also said they did not come stock but because of how popular the DC is 95% of TJs are running them . With this being said I installed the ujoints and took it on a test drive, completely different ride. I did not realize how much vibration a bad ujoint could cause. They guy at the dealership did say when I need a new DS get one with a DC because of their quality.
 
Someone decided to put a Yj style shaft in there. You will want a new front output yoke for the tcase and a double cardan shaft as that is what should be in there.
 
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Jod0001 said:
Ok, update. I went by the off road shop both the guys who have TJs, one of them has 3, must be nice. Anyway I asked about the double cardan and, they said a double cardan was not stock and when I showed a few pics of what I had one of the other guys said that he has the exact same setup as mine. With that info I stopped at the local Jeep dealership in Town, I know a guy who is big into TJ’s he also said they did not come stock but because of how popular the DC is 95% of TJs are running them . With this being said I installed the ujoints and took it on a test drive, completely different ride. I did not realize how much vibration a bad ujoint could cause. They guy at the dealership did say when I need a new DS get one with a DC because of their quality.
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The parts manual for your 2001 shows a double Cardan on the front drive shaft. Your off road and dealership guys are wrong.
 
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TurboTJ said:
The parts manual for your 2001 shows a double Cardan on the front drive shaft. Your off road and dealership guys are wrong.
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I have the original owners manual and can not find any info on the drives shaft, could you please provide the page number. It discusses the front axle, rear axle and T-Case. Is the “parts” manual a separate book?
 
Rickyd said:
If they were talking about the rear then they were right. Who knows what was actually said
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Oh, sounds like my honesty is being brought into question here. Just to be clear there was no confusion on rather it was the front or rear drive shaft being discussed as I brought the drive shaft with me to both shops. It’s fairly easy to identify a front and rear drive shaft of a TJ based off the length alone. I guess I can go back and get a recorded statement if you would like. LOL.
Rickyd said:
If they were talking about the rear then they were right. Who knows what was actually said
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Rickyd said:
If they were talking about the rear then they were right. Who knows what was actually said
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In was able to locate the parts manual, it does list the double cardan in the book. Wonder what those guys will say next time I see them.

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Jod0001 said:
Oh, sounds like my honesty is being brought into question here.
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Lighten up Francis. I'm pretty sure he was just saying that what they said vs what they meant vs what you heard vs what you understood vs what you typed can result in a lovely game of telephone, on top of the fact that it would appear that neither party involved actually knew what was supposed to be there.
 
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hear said:
Lighten up Francis. I'm pretty sure he was just saying that what they said vs what they meant vs what you heard vs what you understood vs what you typed can result in a lovely game of telephone, on top of the fact that it would appear that neither party involved actually knew what was supposed to be there.
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Haha, I didn’t take it to heart hopefully he didn’t either. I need to get the parts manual in paperback form. Can’t remember who referenced it but I’m glad they did.
 
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TurboTJ said:
My observation? This site is a pretty good source of accurate information. Believe it here before you believe other “experts”.
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TurboTJ said:
My observation? This site is a pretty good source of accurate information. Believe it here before you believe other “experts”.
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Yeah I have gotten a lot of help from this forum and will continue to use it.
TurboTJ said:
My observation? This site is a pretty good source of accurate information. Believe it here before you believe other “experts”.
Click to expand...
TurboTJ said:
My observation? This site is a pretty good source of accurate information. Believe it here before you believe other “experts”.
Click to expand...
 
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