242 problems with 4wd

so i have my 89 4.0 aw4 242 combo, never had any problems until tonight when i went to help pull a friend out of a hole that i could not shift my xfer case out of 2wd into any range of 4wd, the shifter just wont move..... i tried climbing under the truck and having someone move the shift for me, it moves all the way down to where it bolts on the xfer case, even the selector rod on the case moves a little, but it just wont click out of 2wd...... any suggestions on what i did, or what i can do to check out if i grenaded the case..... i have no odd noises when driving at any speed, just have no 4wd and it only took me and 2 other 2wd trucks to pull my friend out tonight....... go figure i need it and it wont work..... please help me out here cuz im just dumbfounded at the moment

Have you tried backing it up in reverse, then putting it in neutral, then immediately trying to shift into 4wd? Maybe you haven't used it much and it's got a little stuck. The reversing operation sometimes has worked for me on 4x4 rigs.. I try to "exercise" my 4wd every now and then, even if I don't need it, so I know it will work when I do. -Rick

i haven't used it much at all, and last time i did use it was like 3 weeks ago, and it was really hard to shift it..... i've tried the backing up and shifting thing, forward and trying, neutral and trying, even off and trying...... really stumped here a to what happened

Whens the last time you checked the fluid, sounds like it's empty.

i checked the fluid in it today..... it was a little low, but i still seem to think i toasted the case