NP231 stuck in 4H, NOT linkage problem

[slomorumble]

Hello, mine is a 99 TJ auto trans. She's stuck in 4wd with some faint clanking audible in the driveway (dead slow and about 3-4 clanks per second)... The shifter is actually down in the 2H position and I can only pull it about half into the 4H position. It just doesn't click all the way in. I mean, it does click in but it's not the solid clunk I'm used to. Touch it and it pops back down to 2H. The 4WD indicator comes on only until I release pressure from the shift lever. I cannot shift the transfer case by bypassing the shift lever. Direct actuation has the same half-click effect.

Over the past few weeks, I had been experiencing some intermittent drag with that 4WD feeling about 50% of drive time with it coming and going on its own. Then it became permanent. Other than that, no other irregular noise or performance issues.

The oil seal on the rear output was out of place just flapping in the wind around the shaft, with pieces of the snap ring sitting in the seal's place, as if the shaft had moved in or out of the case and broke it.

Anyone have any idea what has happened here? My thoughts are that I'm hearing pieces of shift fork and there is a jam? Take it apart? Get a used one? WWYD?

 

[superj]

too bad you are so far away. I still have my np231 from when I swapped my jeep to a 302. its the only thing I have left from jeeps in the garage.

 

[JPNinPA]

Do you have body lift?
Tummy tuck?
Dropped skid plate?
Can you verify nothing is blocking the shifter from moving into the 2wd position fully?

Have you checked the oil level in the case?

I'd pull it apart given the seal and noise.
Possible first remove the drive shafts to see the noise is only the case. You will be removing them anyway.


JPNinPA
Using Jeepz.com app

 

[slomorumble]

Do you have body lift?
Tummy tuck?
Dropped skid plate?
Can you verify nothing is blocking the shifter from moving into the 2wd position fully?

Have you checked the oil level in the case?

I'd pull it apart given the seal and noise.
Possible first remove the drive shafts to see the noise is only the case. You will be removing them anyway.


JPNinPA
Using Jeepz.com app

1" body lift, other than that, no dropped t case, or any other mods... Oil was nasty but full...

I think that snap ring at the rear output breaking allowed the shaft to move just enough to engage it with the 4WD synchronizer... It's a fine line between 2 and 4 positions.

I'll take her apart and post my findings...

 

[paradineai]

I have this issue at times. If you put into reverse and allow jeep to roll while moving the 4x4 lever back and forth from 2x4 to 4x4 without really going all the way to 4x4 then it should "slip" into 2x4 mode. While doing this you may even have to turn your steering wheel as far to one direction as it can go so you end up turning in a circle.

Doing this has gotten my selec-Trac case out of 4x4 mode several times. The biggest cause is that I need to rebuild the case as some of the guts are worn and need replacing before they break.

Sent from my SM-J320V using Jeepz.com mobile app