There's still quite a bit of surface rust that needs to be cleaned and the "gravel" sound is from the rear bearing (the one behind the chain) for the _front_ output shaft.

Does anyone know why the detent plug would keep the TC from shifting. Is supposed to be screwed all the way in or is it supposed to be partially unscrewed?

I would guess it goes all the way home and the spring does the rest. Did you price a TC at your JY? Odds are you could find one that somebody didn't use much. Just a thought. I might compare that to buying new bearings and doing all that work.......

Are all of the NP231 J TCs the same from 1987-2001? I'm basing this off the wikipedia article on the XJs (http://en.wikipedia.org/wiki/Jeep_Ch...Transfer_cases)

no you need a 1987 thru 1990 case behind a 4.0 so the spline count matchs up to the tranny

Thanks freegdr. When I was originally looking for parts in the JY for the Jeep, the oldest XJ I could find was '94. I'm sure there is one out there and I'll call all of the JYs in the area tomorrow to see what I can find.

For knowledge's sake though, I still want to figure out the TC I have so I can work on it later on.

there getting harder to find good luck some times e bay will have them just make sure it come from same tranny type to avoid any issues

I got the TC stripped down and found that the lope in the rear output shaft was from 2 blown bearings. Actually, all of the bearings except the front yoke bearing and the pinion bearings in the low range gear.

I'm still not sure why the detent pin is keeping the shift selector from moving.

Any thoughts?

It moves Ok with the ball/spring removed? That spring compresses?, it's not seized? Gotta figure the detent is too deep? Maybe rusted from the water.

If you loosen/remove it, shift to another position, then re-install it, it locks there?

Correct. Everything moves smoothly with the plug removed or backed out a good bit. The spring that's in it is extremely strong and almost impossible to press together by hand.

When the plug is screwed all the way in, the pin seems to seat too well with the shift selector.

Well, I got curious enough to spend a while getting lost in the FSM this morning. I thought maybe they might show a spek for that spring pressure. Not.

Did you pull the spring out of the popit (yea that's what its called!), pull the spring out and make sure there isn't gunk keeping it from compressing?

Idk. If I was in a real jam there I might try a different "assembly" there with a different spring, and/or a different selector plate thingy with the teeth. Or take a file to that one.

I took the main shaft to my uncles garage and had him press the drive gear off of it because the gear and the bearings had seized (read "rusted") to the shaft. Turns out the lope I was seeing on the rear output was due to the main shaft being warped by about 1/8". So much for that TC. I'll keep the salvageable parts for replacements if i need them later.

Thanks for your input, flintsone. It was appreciated all the same.

Well Bummer Yea, something didn't sound right when the word "lope" came on the scene. (Well, seized, dry and leaking was a clue!). I did wonder a second how a bearing would do that. AND what the heck did that I wonder. Maybe the drive-line coming off. Good luck! Maybe someone with an 87-90 T-Case will see this and PM you.

Yeah...I thought (read "hoped") it was something other than a warped shaft. Meh, you win some you lose some. I have found a replacement TC in a junkyard about 2 hours away. At least I know what I'm doing this weekend

MMMMM. Besides looking at the fluid, I wonder if you can get an idea of the slop in the chain by turning the front out-put yoke back and forth?

well if your planning a lift you will need a sye. It comes with a main shaft and a new tail you could pick up a rebuild kit and rebuild this one if the case itself is ok... Just my .02