I am hearing a dull noise at low speeds on my 01 F250 PS. 128 K miles. I jacked it up and ran it and there is a little noise at the transfer case where the rear drive shaft connects. It isn't a grind but it isn't a squeak either. If I wasn't anal about every little noise I would likely not notice it. Drives fine. I am about to take off on a 2500 mile round trip and now I have myself worried. Is there a bearing there? It sounds like a bearing might be getting weak. Transfer case fluid is clean and at the proper level. Transfer case shaft the yoke connects to doesn't seem to move when I push up and down on it. Noise goes away if you shut the engine off and let it coast. Doesn't go away if you just put it in nuetral and let it coast with the engine on.