Used NP231 with SYE and driveshaft worth it?

DB04RedJeep

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A used NP231 with a SYE installed that was behind an AX15 transmission is listed on CL for $500 about an hour away from me. I have a 2004 X with a NV3550 transmission.

Is something like this worth looking at or would I just be asking for trouble? And would it even bolt up directly to the NV3550?

My next project (of many) for next year is to get rid of the 1in TC drop along with replacing all the CA's. That's why the thought on the SYE.

The lift is a 2.5in OME. If also I'm understanding it correctly the addition of a 1in motor mount lift and a bodylift could also work on getting rid of the TC drop so the SYE would not be needed.

Would this still allow the use of factory CA's or would adjustable's be needed? The plan is to stay on 31in tires, for what we use it for the size is perfectly fine.

I just want to do it right and not have to keep doing it over to get it right. Time is my biggest issue to do things. Thanks
 
is anything wrong with your current 231? the advance adapters SYE kit is on sale at quadratec for only $220 right now
https://www.quadratec.com/products/52237_99_07.htm
keep in mind you need a new rear driveshaft for this conversion.

Are you actually sure you need the TC drop with only a 2.5in lift as is? were you having vibration issues before?
 
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is anything wrong with your current 231? the advance adapters SYE kit is on sale at quadratec for only $220 right now
https://www.quadratec.com/products/52237_99_07.htm

keep in mind you need a new rear driveshaft for this conversion.
Are you actually sure you need the TC drop with only a 2.5in lift as is? were you having vibration issues before?

Current 231 is working fine. Just thinking it might be easier to switch them out, again just thinking. If I put a SYE in my current 231 would it be the smart thing to rebuild the TC at the same time? I'm trying to keep down time to a minimum.

Yes understood a new DS would be needed. I have a $200 gift certificate to use at Tom Woods Driveshafts.

Yes need the TC was having vibes, no vibes with the drop. Thanks for the feed back.
 
SYE is an easy install, my $0.02 cents is pick up that sale on the AA SYE for $220, do the install yourself!
id be happy to chat on the phone if you need help w the install and there's also some good documentation posts here
 
500 seems expensive to me. But I've reached the age were I can't buy a candy bar without bitching about the price.........

How many miles are on your transfer case? At least with yours you know the history of it. Just a thought.
 
Are you actually sure you need the TC drop with only a 2.5in lift as is? were you having vibration issues before?
Every Jeep responds differently even to the smallest of lift changes.
The change in driveshaft U joints angles especially if the the U joints are older can cause vibrations.
When I installed a 2" coil spring lift my '01 ended up with driveshaft vibrations; the interim installation of a 1" drop of the TC skid plate cured the vibrations until I could afford to purchase a SYE and DC driveshaft.
NOTE: After installing the SYE and new DC driveshaft it is recommended to measure the rear differential pinion to driveshaft angle. A Zero degrees difference in recommended and can be accomplished with adjustable rear upper control arms.
 
For me it all comes down to knowing the condition of what you have in the end. If your existing 231 is in great shape then no need to rebuild-install a sle, order and install a new driveshaft and adjustable control arms and be done with it. As for the 231 with the sle installed, I am always wary of buying mechanical components unless I absolutely know the history and thus have an idea of what I need to do to address issues. If you don’t know the history, you might be rebuilding it.

And installing a sle really isn’t that big of a deal-I didn’t even remove the TC from under the Jeep to do it.
 
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For me it all comes down to knowing the condition of what you have in the end. If your existing 231 is in great shape then no need to rebuild-install a sle, order and install a new driveshaft and adjustable control arms and be done with it. As for the 231 with the sle installed, I am always wary of buying mechanical components unless I absolutely know the history and thus have an idea of what I need to do to address issues. If you don’t know the history, you might be rebuilding it.

And installing a sle really isn’t that big of a deal-I didn’t even remove the TC from under the Jeep to do it.

how did you install SYE without removing the TC?... the case halves have to come apart and the entire main shaft is removed and replaced
 
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how did you install SYE without removing the TC?... the case halves have to come apart and the entire main shaft is removed and replaced

Pretty straightforward-you just unbolt the back half, remove it, and take the guts out. With a lifted Jeep there is lots of room to work. Unless doing a full rebuild and installing new bearings and such, I don’t know why people take the entire TC out just to install a sle.
 
Sold my 231 w/ SYE and the driveshaft for it for 500.
It was running great. Had it gone though and new seals installed.
The Driveshaft was rebuilt by a local driveshaft shop and had new Spicer u-joints and Cvd ball.
I would have still be running it if I didn't go to new transfer case.
 
SYE is an easy install, my $0.02 cents is pick up that sale on the AA SYE for $220, do the install yourself!
id be happy to chat on the phone if you need help w the install and there's also some good documentation posts here

Thank you the response. I will have to search the site more to read up on installing an SYE.

I can't remember where I was reading something about installing one and it seemed more complicated than I thought, but again I could have been reading about something else. Thanks for the help offer, if I do it I will probably take you up on it.
 
500 seems expensive to me. But I've reached the age were I can't buy a candy bar without bitching about the price.........

How many miles are on your transfer case? At least with yours you know the history of it. Just a thought.

Everything is expensive now :( I have no idea on the mileage it popped up when I was searching for parts on CL. Agree I know the history of mine and I'm probably opening a can of worms getting into something used with no back ground info.
 
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Every Jeep responds differently even to the smallest of lift changes.
The change in driveshaft U joints angles especially if the the U joints are older can cause vibrations.
When I installed a 2" coil spring lift my '01 ended up with driveshaft vibrations; the interim installation of a 1" drop of the TC skid plate cured the vibrations until I could afford to purchase a SYE and DC driveshaft.
NOTE: After installing the SYE and new DC driveshaft it is recommended to measure the rear differential pinion to driveshaft angle. A Zero degrees difference in recommended and can be accomplished with adjustable rear upper control arms.

So if I do go a head with installing an SYE I will need to go with adjustable CA's?

Which I have no problem going with because the stock ones are needing replacing. I'd rather get it all done at once if I do it.

Sorry for another question are still running the stock skid plate?
 
So if I do go a head with installing an SYE I will need to go with adjustable CA's?

Which I have no problem going with because the stock ones are needing replacing. I'd rather get it all done at once if I do it.

Sorry for another question are still running the stock skid plate?

With the 2" lift that I installed I was able to achieve a 1* difference with one adult male in the Jeep which has provided no vibrations.
You will need to test the DC driveshaft to pinion angles to know for sure if you will or will not require rear adjustable upper control arms.
Yes... I am still have the stock skid plate installed.
 
With the 2" lift that I installed I was able to achieve a 1* difference with one adult male in the Jeep which has provided no vibrations.
You will need to test the DC driveshaft to pinion angles to know for sure if you will or will not require rear adjustable upper control arms.
Yes... I am still have the stock skid plate installed.

@CharlesHS thank you for the feed back. The more I look at it doing the SYE to my TC is the smarter way to go instead of the possibility of a can of worms with something used and unknown.

Looks like it's time to start squirreling away parts over the winter. My CA's need to be replaced anyway so maybe I'll just replace them all with adjustable CA's and be done with it.