Hi guys, I drive a 1999 xj sport and for some reason 4H doesn't work at all.
I have fluid and 4L work fine and when the stick is in 4H and i let the clutch out, it's as if it is in neutral.
If anyone can help me and share some jeep knowledge with me, I'd appreciate it.

 

This is either:
A) An issue with the transfer case internals such that the selector can't trigger the shift to 4H.
or
B) The selector is not moving to the correct position.

In the case of A, the only way to correct this is to open up the transfer case - which at that point it might be worthwhile to just do a full rebuild of it. This is the worst case scenario.
In the case of B, it may be an issue with your linkage (and the stock linkage on these is prone to wear and bending).

I'd try pushing the stick a little bit less than "fully" into 4H and see if it engages - wiggle it a little bit. If it still won't go into 4H, I'd crawl underneath and try to engage 4H manually. It should sort of "click into place" at 4H and 4L - see if you can get the lever into the right spot and engage 4H.

 

This is the lever to manually adjust. It's kind of a tight spot though.

https://www.cherokeeforum.com/f2/np2...itions-141080/

 

How did you determine 4hi doesn't work?

 

He mentioned that he puts it in 4H and lets out the clutch and it acts as if it's neutral, but 4L is functioning correctly.

Edit - And presumably 2wd is also functioning correctly - though I don't want to put words in the O.P.'s mouth.

 

Then I think the answer is that the linkage simply needs to be adjusted. A common thing since our linkage is kind of a joke anyway. There is an adjustment nut on one of the rods that allows you to move the rod and not the linkage. Manually put it in 4hi while the rod is loose then tighten and that should get it