NP242 engage/disengage issues

[DK_XJ_1992]

I have some trouble with my TC and I was hoping to get some advise here. It is a 92 4.0, with a AW4 and a NP242 behind. I have had it for 20 years. The last 6 years it has been parked due to long commuting distance. I have used those year to fix rust and other things. 6 months ago I got it back on the road and use it everyday (app 50 miles). Last week we had some heavy snow fall and I tried to engage 4wd. However, it for sure did not feel like it engaged. I tried all the trick with driving slow, shifting to N and tried both 4H part time and full time. Nothing seemed to work. The 4wd light never came on, but it has always been very unreliable. I managed to get home, put the TC back in 2H and parked the jeep for the weekend. Then yesterday all snow is gone and it is 55F. On my way to work and back it made some unusually noises. When I drove into my driveway I could feel the characteristic bump steer when you use 4H part time on dry pavement. So in some way it now when into 4H part time and refuse to come out, and I assume that I drove 50 mile on dry road in this mode. As it is my daily drive I removed the front driveshaft and replaced the TC oil with some Dexron II I found in my shed, so I could use the jeep today. This evening I had the chance to do some diagnostics. Both axles seems find there is no major backlash in the gear and no shavings or metal in the oil (Pic 1). The oil from the TC was dark, but did not smell burned nor had shavings in it (pic 2) (it had 1½ qt in it). It is not a linkage issues as I build a replacement some years ago with hemi joints, and the adjustment is spot on (pic 3). I feel all the position very well.
When the TC is in 2H by hand I can only turn the front drive shaft pinion counter clockwise. Shouldn't it run free in both directions?
When it is in 2H and it is turned it makes a rather loud noise (video). Is this normal?
When I change the TC to any other position then 2H I cannot turn the front drive shaft pinion by hand.
I really hope that I can get some advise, so I can consider some different options. There are no pull and pick junkyard where I live.
I do have the option to borrow another car if I need to take the TC out.
As I don't have enough posts to upload pictures they can be found in this link: https://drive.google.com/file/d/1B7Pq0ppnoXlZlp_wHXOYAKyjLu2AWp01/view?usp=drive_link

 

[Tim_MN]

The 242 is known to be stubborn about shifting between the different modes, and back into 2wd. Installing one of the aftermarket shift linkage mechanisms often improves the shifting.

I might suspect that the tabs on the shift fork are well worn and need to be changed out and/or that shift linkage mechanism could use some fine tuneing.

 

[RCP Phx]

That ratcheting would suggest something in the interaxle diff has let go.

 

[DK_XJ_1992]

Thanks for your replies.
I forgot to mention that it has 160k on it.
The linkage is not the original and it is adjusted.
I have use it the last week in 2H mode, but without the front driveshaft. Now I can easily spin the front output pinion on the TC in both directions.
If I put it in 4H full time without the front drive shaft the open diff in the TC should prevent it from moving. Can anyone confirm this?
I will try to shift between 2H and 4H to see if the oil change fixed the sticky gear.

 

[Unclewolverine]

Mine have always been sticky to engage/disengage. At about 350k my last one was worn to the point it wouldn't go into low. Never needed a chain though! Jeep was totaled at 416k.

 

[DK_XJ_1992]

So I finally got some time to update my diagnostic. I was i doubt if it should be able to drive in FT4 without the front drive shaft in place. I my case it was able to drive. So I swapped the rear to the front as I know from earlier that without the rear drive shaft it will not drive in FT4, and sure it was still able to drive. Now I have pulled the TC out and disassembled it. First I found some minor shavings on the magnet. Both shifter forks are intact with the nylon things in place. Only very little wear to be seen. Nothing wrong at first. After digging deeper I found that some of the teeth in the planetary/differential had been grinded half off (see picture in link). https://drive.google.com/drive/folders/1CshNtfgtTftMmh8rcrOpBi9OSwo6n7iS?usp=sharing
First I don't understand how grind that small bit of the teeth can prevent the TC to shift between PT4 and FT4, any suggestions?
I'm looking to find some replacement parts. I think a used NP242 is the cheapest way to go, but I'm not able to find any that match in year. So I was thinking to get a NP242 from a WJ or ZJ and then swap the internals except the input to my old TC. Is this a possible route? I was thinking to get a reman TC, but since I'm in Europe it is to expensive to return the old (600$ core charge), so I will be looking into spending 3000$. I can get a WJ NP242 for 300-400$ and a rebuild kit for 100 or so.
Any thoughts?