hi guys.

1996 gmc sierra 2500 hd transfer case noise

need some help with what i hope is not going to become a problem. my 96 has never given me problems before. but a couple of days ago driving along at about 60 km/h heard a couple of load low pitched squeals (like a dry bearing) from under the hump. thought "oh no, tranny" - pulled over and checked, nothing obvious. kept going and no more sounds. last night at 100km/h heard/felt intermittent vibration from same area, but very slight. this morning checked universals- fine, checked tranny and transfer case fluids - fine and good looking (both done only 10k ago), can't see any leaks or anything. i know this is pretty non-specific but i am wondering if there is a known problem in and around the transfer case/tranny on this truck that i could look for prior to blowing up either or both. or is it just wear and i have to accept it. have read many posts on same area, but not same problem