This weekend was the first time I tested 4 low in my 1992 XJ I bought last year. I put the transmission in neutral and the transfer case into 4L, As soon as I tried to drive forward (up a steep section of jeep trail), it slipped out of 4L immediately upon moving forward. I tried multiple times, with the same result. 4H seems to work. I am wondering if there is a process that I don't know, or if the 4L needs to be gone through. Honestly, I don't know a lot about the automatic transmission and auto hub version of jeeps. All my previous jeeps have been manual transmission with manual hubs.

Couple things. How you shift, linkage adjustment, and bad engine/trans mounts.

Here's how the factory suggests you shift the transfer case and I've been doing this since these things were new and I worked at the dealership. Quoted from the owner's manual. The suggestions in CAPS are mine.

"To engage, shift the transfer case lever from 2H to 4H while the vehicle is moving at any legal speed". I LET OFF THE GAS, THROW THE LEVER, TAP THE GAS AND LET OFF.

4L position: " To engage, slow the vehicle to 2-3 MPH , shift the transmission to Neutral, then shift the transfer lever to the right and pull firmly rearward to 4L".

TO SHIFT OUT OF 4L, SHIFT THE TRANSMISSION INTO NEUTRAL WITH THE VEHICLE STOPPED, SHIFT THE TRANSFER CASE LEVER TO 2H, THEN THE TRANS TO D IF YOU HAVE AN AUTOMATIC, OR INTO FIRST GEAR WITH A MANUAL, AND CONTINUE ON.

Sounds the shift linkage needs adjusted, I have had to do this on two jeeps with the same issue.

Here is a vid on how to adjust the Transfer case linkage..

https://www.youtube.com/watch?v=BHp2...ature=youtu.be

After you have verified engine and trans mount condition