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Unread 01-21-2014, 12:20 AM   #1
imstillatwork
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1993 YJ Wrangler 
 
Join Date: Aug 2009
Location: Oregon Coast, Oregon
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NP231 metal in oil, no noise, ???

I rebuilt the transfer case about 3 or 4 years ago. All bearings, seals, and a new chain. Easy enough, went smoothly.

A about two months ago or so the transfer case stuck in 4wd. I let it sit since I was going to pull to motor anyways...

...Today I took apart the case to install the new input gear for my 4.0 swap.
The fluid was dark grey and the magnet was furry! That's not good. Bearings are going bad SOMEWHERE! I haven't noticed any unusual noise at all from the transfer case over the years.

Found out why 4WD was stuck. The syncro ring was stuck on the sprocket, so the mode selector collar would not engage, so the selector arm would not budge. Weird, because a little tap (ok, a few decently hard taps) and the syncro ring fell off. It was not galled, burnt or otherwise damaged.

Do you think the fouled oil caused the syncro ring to stick without causing any damage???

On to the bearings.

The front output toke is solid, no play, no noise. I put the front sprocket shaft end in the captured bearing inside the case and it's quite as well.

The rear output bearing is solid as well, smooth and quite.

The input bearing seems fine as well. I inserted the input gear without the planetaries and it spun smooth and quite.

This leaves the cage bearings on the main sprocket. The LOOK OK, not burnt, no signs of damage, but they are a little scratchy sounding when I spin the sprocket on the shaft.

I'm guessing my bearing problem is the cage bearings on the sprocket.
Is the new style shaft & sprocket without bearings a worthwhile upgrade?

If I upgrade my hack & tap to the Super Short SYE, then I would not need to shorten my drive shaft when I install the 4.0...

I could kill two birds with on fix, right? Super Short SYE eliminates the cage bearings, and reduces transfer case length over my hack & tap buy about 2.5" negating the need to shorten my drive shaft.

Man, am I over thinking this or what....

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Unread 01-21-2014, 09:11 AM   #2
StanF
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Quote:
Originally Posted by imstillatwork View Post
snip
If I upgrade my hack & tap to the Super Short SYE, then I would not need to shorten my drive shaft when I install the 4.0...
snip
Great plan! This is what I intended to do when I did my 4.0 upgrade. Your speedometer may be off after the Super Short upgrade, so you might need one of the little correction boxes from Blue Monkey or a similar product. More $, unfortunately.

Sorry, I can't offer any meaningful help on your transfer case questions, but I would be tempted to install a complete rebuild kit and chain on it to ensure that I fixed all the issues. The problem is that will cost $$$, and the Super Short SYE is expensive too. Here's my thread on a similar topic:

http://www.jeepforum.com/forum/f12/t...build-1896249/

(BTW, you will need to lengthen your front driveshaft after the 4.0 swap)
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Unread 01-21-2014, 01:15 PM   #3
imstillatwork
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Yep, I try to plan out for the big picture...
I don't want to rebuild after just 4 years or mild use. I'm tempted to just do the Super Short SYE which will eliminate the bearings that I think are bad.
I really hope that the syncro ring got stuck due to poor lubrication. With the grey ATF in there it would almost stick by hand as it gets pressed onto the tapered shaft. With clean ATF I could press as hard as I could and it would still release freely.

I don't really want to spend 300 on SYE, but it would save me 100 in shortening the driveshaft, and a longer driveshaft is better anyways. And if it would solve the bearing issue, then hey. good deal.
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Unread 01-21-2014, 01:16 PM   #4
imstillatwork
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I think I need to figure out a way to post with less words and fewer choices. I usually don't get many replies
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Unread 01-21-2014, 01:42 PM   #5
Randonexplosion
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Ha. I think that's a good idea. Just clean the hell out of the bearings with brake clean when you put it all back together.
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Unread 01-21-2014, 10:05 PM   #6
imstillatwork
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1993 YJ Wrangler 
 
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Location: Oregon Coast, Oregon
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Ordered Super Short SYE from JB conversions and 1310 CV Socket Yoke 211355X from northern to convert my CV drives haft from flange to yoke.
The JB flange option is $100, and 3" pattern. My CV flange is 3.25" pattern. I can get the $60 socket yoke from ND to fit the JB yoke, fix my slightly worn center ball / socket AND save $40.
After I sell off the hack & tap it should end up being a very affordable upgrade. And if all goes well I don't have to adjust my rear drive shaft. It's Win win, win, win, win...win.
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