XJ CHEROKEE NP242J transfer case problem

[The Nicho's]

Hey all,
Got a problem in the wifes transfer case yet again and I need help Identifying if i need to replace it or if its just simple adjustment.
The problem is, While driving you get a distinct but dull thunk which is continuous as you drive in 2 wheel drive, I jacked up the front after selecting 4L and turned the front wheels which they did to my surprise, While turning the wheels you can easily hear what sounds like a clunk and it almost feels like there is a tooth missing off a gear or something inside the transfer case and through the wheel you can easily feel this. Not to sound dimented but as you turn the wheel its like a donk donk donk donk donk coming right through the drivetrain from the TC.
Any suggestions or ideas would be greatly appreciated.
And if it is the TC does anyone have a NP242j for sale. This would be the second time we have done a TC on this jeep but it does constant 4x4ing for work and is regularly serviced including all fluids by me. I just think this last box I got (second hand kms unknown) was a dud from the begining.
Cheers
Nicho

[Steve F]

Could be the front driveshaft as this spins all the time even in 2WD, maybe pull the shaft and then go for a spin with it in 4HI (part time as this will mean there is drive to the front and will spin the t-case internals). If the noise is still there then it's probably the tcase, if it's not then it could just be unis on the driveshaft or the ball centering unit worn in the dual cardan joint.

Cheers
Steve

[The Nicho's]

Thanks Steve, the noise is definitely coming from the transfer case. You can distinctly hear it when laying under the jeep while the wheels are being turned.

[junglejuice]

Where are you located?

[The Nicho's]

Pakenham Vic