RickT

I have a 98 XJ with an auto trans. Recently I noticed a noise that almost sounded like an engine knock. Upon checking, its not an engine knock but seems to be coming from the transfer case. I tried shifting into 4WD and I get a lnocking sound, the 4WD light doesn't come on. I've been told it's probably the chain in the TC. The weird thing was the last time I used 4WD, a couple months ago, it worked fine. Would the TC develop I problem while not in use? Also, it seems to run fine in 2WD, other than hearing the noise. Will driving it in 2WD do further damage to the TC? Thanks!

VTJeep

yes, it might be the internal chain in your TC, more likely though, your front drive shaft is on its way out. i had a similar issue w/ mine recently (99 xj w/ np242 and aw4) it was fine in 2wd, but engage it in 4 and there was a noise (that got progressively louder as time went on) like grinding metal. i thought for sure it was the TC, but fortunately it was the front drive shaft. mine was like 90 bucks and i woulda installed it my self, but one of the 8 bolts was stripped so i didnt wanna bother...

your other option is your linkage between TC and shift lever needs to be adjusted. if they get some play then it wont fully engage 4wd and will want to pop outta 4... there are plenty of write ups about adjusting the linkage.

hope that does the trick... oh, yea, you can generally tell if its the TC by using a stethoscope, put it to the TC and see if it sounds like it is in there, if your having a hard time pin pointing it then id say prob the DS...

RickT

Thanks much for your quick and helpful reply. Everything you said makes perfect sense. I'll dig deeper into the diagnosis, based on your suggestions, this weekend.