Q&A

Hard to guess without hearing the noise. The front axles are forward/ mid engine compartment area. The transfer box and drive shaft are in the area you talk about hearing the noise, very important to get it checked out on many 4WD cars if the front Universal Joint on the drive shaft brakes it could potentially flip the truck over.
There is a company that independent auto repair shops "buy" their information from that offer a very reasonable service to do it yourselvers. You get a one year subscription to year make and model specific repair procedures, service bulletins, component locations, wiring diagrams ect.... great quality information same as the professionals have ,much better than generic workshop manuals from parts stores, much cheaper than the factory manual. try http://bit.ly/mitchell_repair_manuals_online and get an online repair manual subscription.

had a similar problem w ours it turned out to be the swaybar link it went out of socket eventually