Yeah I checked it and looks fine. I checked transfer case too. How did you do that check when problem only happens when moving? It started after I let my mom borrow my truck long time ago and she engaged 4wd when it was snow packed underneath and threw something out of whack. Still trying to ffigure a way to pin point it.
I believe my front differential is causing a grinding noise and just looking for some other opinions. I only hear the noise when 4x4 is engaged. I'm 99% sure that its the front differential causing the problem because when I last changed the fluid (only 25k miles on it) it came out not burnt or anything but all metallic, looked like liquid metal it was so grey, magnet was completely covered in metal. Wasn't any big shards just like a fine dust if it was dry. Would this be the bearings? How difficult is it to remove the differential and tear it apart?
it turns out I did have some bearing issues in the front diff but it was not the noise after rebuilding the front diff I still heard the noise in four wheel drive and for me it was the transfer case it developed pump rub which is come in a np263xhd. what happens is the clips that hold the oil pump down break and the oil pump rubs holes in the rear case half. so I was running my transfer case with no fluid in it so I am rebuilding it here in the next two weeks but for a temp fix I plugged the holes and filled it with fluid. I still don't use 4x4 yet but it hasent blown out yet. if you have this issue there is a upgraded pump you have to install or you need to install a case saver