No 4HI in '99 XJ with 242 help!

On my '99 with the 242 TC only the 4LO is working... 4 full time and 4 part time do not seem to want to engage.

I took a look at the linkage, it appears to be fine, not bent or anything. (I do not do any major off roading, the rig is stock for the most part).

Would changing the fluid make any difference? I don't notice any grinding sounds or anything like that....

Any suggestions on what I could try? Any help would great!
Thanks

Anyone had somthing like this happen to theres?

One quick way to see if the front differential is energized is to shift the t-case lever into 4hi and then put a hand on the front driveshaft and try to turn it. If the driveshaft turns, it is in 2wd. If the driveshaft has resistance, then the t-case is in 4wd.

Maybe not as Lodi Jim says. Unless you have the front axle disconnect feature and it's NOT engaging, the front driveshaft will always have resistance unless the front wheels are off of the ground. I don't think the 242's were paired up with the front axle disco feature (mine is a 242 and doesn't have that feature).

With both 4Hi settings not working, I'd suspect a linkage adjustment first (easiest to check and fix). After that...probably something internal to the transfer case. Good luck!