i have a 98 recon and there is a random grinding in the rear axle. it sounds like it could be a pit in the bearing or some dirt in it but im not sure. the metal bearing seal slides out all the time and just slides back and forth on the axle so thats what makes me think its a bearing. but according to my repair manual it says any noise in the rear axle such as knocking or growling could be signs of final drive problems and it also says that noting if it happens when your accelerating or coasting and if your turning or going straight but it doesnt tell you which noises mean it is something with the final drive.