If you try this set the E-brake, block the tires, with the truck "off" put the truck in "N" then get under the truck and try to manually shift the t case.

 

I mentioned before that i had been under it to inspect...as of now Ive already been all over the truck...I'm no stranger to the undercarriage...as i said it appears to have its share of corrosion but is intact.

My 90 yj had a retainer clip issue that would allow the shift lever to be pulled up off of it and the pinch bolt in the linkage was an issue...there were a few times i needed to get under it and manually shift it at the tcase before i fixed it....interestingly it was also a np231

This is what ive been trying to acquire knowledge about...what potential problem may cause it to be stuck?

 

Thanks for the tip, I'll give it go tomorrow morning.

 

Try to manually shift the tcase first and see what happens..

 

If you can't shift it by hand under the truck, then its time to take it apart and see whats going on.

As per the FSM

TRANSFER CASE DIFFICULT TO SHIFT OR WILL NOT SHIFT INTO DESIRED RANGE

(1) Vehicle speed too great to permit shifting.

(2) If vehicle was operated for extended period in 4H
mode on dry paved surface, driveline torque load
may cause difficulty.

(3) Transfer case external shift linkage binding.

(4) Insufficient or incorrect lubricant.

(5) Internal components binding, worn or damaged.

(1) Stop vehicle and shift into desired range. Or
reduce speed to 3-4 km/h (2-3 mph) before
attempting to shift.

(2) Stop vehicle, shift transmission to Neutral, shift
transfer case to 2H mode and operate vehicle in
2H on dry paved surfaces.

(3) Lubricate, repair or replace linkage bushings or
tighten loose components as necessary.

(4) Drain and refill to edge of fill hole with
DEXRON II® or MOPAR-MERCON® Automatic
Transmission Fluid.

(5) Disassemble unit and replace worn or damaged
components as necessary.

 

Good post Merc. I was going to mention fluid checking. I'll provide a picture of mine here just for reference.

 

By the way merc225hp I've been following the Tcase busted thread, awaiting your solution..hope you get another one to fiddle with.

I also read somewhere on here about clunking while med. to hard braking, i believe it was in that thread actually, about early detection, wondering if this could be related,

I did notice today a clunk under med. braking and it triggered my memory of its mention.

 

Now thats the kind of info i was shootin for, thanks so much to all of you, will update tomorrow to let you know how it goes.

man i got get me a pic account somewhere so i can post pics

 

You can obtain free downloads of the factory service manual and parts manual in the DIY/FAQ subforum, which I suspect is where Merc got that info. Additionally, a Haynes manual is able to fill in other holes.

Good luck and look forward to your findings as it may help others.

 

Photo Bucket is popular ez to use and free http://beta.photobucket.com/