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jeepbreaker 06-11-2008 12:43 PM

Help with NP231 problem
Having a problem with my np 231 transfer case, any help would be appreciated.

I broke a ujoint in the rear driveshaft of my 92' yj so i put it in 4wheel to drive it home with the front axle, it drove about ten feet then i heard a noise in the transfer case and the front axle quit working. I thought it might be the Drive chain but opened up the yoke case to find that the chain is fine :banghead:.

Does anybody have any ideas of what else it might be?

jpdocdave 06-11-2008 05:19 PM

not sure what went wrong, but if you still have the slip yoke, all the fluid will come out tail shaft of the t case without the d shaft in it. sye this isn't an issure

yjwrangler 06-11-2008 07:20 PM

well elaborate on the story. did you drive it home anyway? did it just pop out of gear?
did you re-fill all your fluids? whats up

crafty 06-11-2008 07:32 PM

Thats not it, I did the same thing and drove it home about 30 miles. No SYE at the time I did this. Maybe it was already out of fluid :confused:

jeepbreaker 06-12-2008 07:30 AM

The fixed yoke was still in the transfer case as the ujoint broke on the front of the rear driveshaft. I unbolted the back ujoint then put it in four wheel to drive home. i got about ten feet then heard the noise in the transfer case and then it would not run in four wheel drive. Even in two wheel drive the fixed yoke was not turning when it was in gear after i heard that sound.

This all happened about 2 miles from my house. I was able to get it towed back to the house with some help from my father in-law.

When I opened the drain plug there was still fluid in the transfer case. At first I thought it was the drive chain in the TC as neither the front or rear driveshafts moved but when i pulled the fixed yoke housing off the chain was just fine.

jpdocdave 06-12-2008 09:56 AM

is it a fixed yoke sye, or the factory slip yoke. the stock yoke will still just slide in and out without the rest of the d shaft in. if its slip yoke, maybe the yoke fell too far into the t case and did damage, never seen it happen, but if a d shaft is too long it can push too far into the t case.

if the chain is fine, maybe a main shaft broke or something.

jeepbreaker 06-12-2008 11:28 AM

It's a factory slip yoke. At some point I am going to swap out my axles for a D44 and a D60. When I do that I am going to put a sye and a tom woods driveshaft in it. I may just order the Tera Low 4:1 replace the innards and try and do the sye and axle swap at the same time. Thanks for the help yall.

jpdocdave 06-12-2008 12:58 PM

great time for an upgrade:D

whitebuffalo 06-12-2008 01:49 PM

are you sure its the tcase and not the tranny?

jeepbreaker 06-12-2008 02:07 PM

I'm not sure of anything anymore. Is there a way to test whether or not it is the tranny without pulling everything off and out? The tranny seems to shift fine.

whitebuffalo 06-12-2008 02:12 PM

did you pull the tcase to check the chain?

jeepbreaker 06-13-2008 07:28 AM

i pulled off the slip yoke case and could see that the chain is fine. That's as far as I got though.

whitebuffalo 06-13-2008 08:00 AM

try pulling the tcase off (if its trashed or to do the 4:1 it'll be easier out anyway).

then, turn the output shaft of the trans with it in gear and see if it turns. if it does, you have trans problems, if it doesnt, id start looking at the input side of the tcase. tcase comes apart easy and is fairly simple design, you oughta be able to tell when you pull that main/input shaft if theres carnage.

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