The car now is single

the 4wd disconnected

I dunno what have caused it

my 4WD shifter moves up and down so easy even if the car is off


there is no 4wd hi or 4wd low , the shifter is just moving without connecting to 4WD mode



any one have an idea ?

 

There's a few threads on this. Basically there is a plastic fitting that connects the shifter to bar out of the transfer case. I just had this happen to me this past weekend which is a pain in the arse.

For a quick fix, you can zip tie the 2 pieces together to get your gear set, but it should be covered under warranty.

On a side note, this issue is happening so frequently, I am surprised there hasn't been a more solid solution offered up by the dealers / Chrysler.

 

I can't link threads easily from my phone so do a quick search and you should find the fix is relatively easy with a zip tie (assuming you just popped the linkage cable). Sorry for the lack of technical terms.

Edit: Kahuna beat me to it while I was fumbling with my phone.

 

Same thing happened to me. It is the cable that connects to your transfer case under the Jeep. Take a look at this thread

https://www.jk-forum.com/forums/jk-show-tell-33/broken-transfer-case-link-85588/

A lot of people have had the same problem. Serious design flaw with the JK. Several fixes in the posts as well. Good luck.