I have a problem w. my 4WD also, when i attemp to engage 4wd Hi the button flashed and a wierd grinding noise occurs then it goes back to 2wd. I press the 4wd Lo button and sometimes it supposivly engages in 4wd lo but it seems as though something could be at fault. Ive had my 96 4 door Jimmy for about a yr and the 4wd has worked fine up untill now, any suggestions to get me on the right path here?