Re: Font Differential Noise..
Likely your bearings are shot, and possibly your ring and pinion are worn or damaged due to lack of lubrication.
The easiest option for a kinda-diy'er would be to find a junkyard front axle housing assembly fully loaded from a wrecked vehicle and swap it in.
The other option that takes a bit of know how and strength, would be to overhaul it yourself. pulling the front cover and inspecting the damage would be the first step. there is bearing preload, pinion depth, backlash, and turning torque (a sign of preload) in various stages to worry about. removing bearings would be nearly impossible without decent tools (a bearing puller most prefered but a die grinder and an air hammer are decent too)... The good, you could probably overhaul the entire front end for 500 bucks including a new ring and pinion (considerably less without). The bad... you could spend 500 dollars and if not set up right be right back where you were before with major noise and eventual failure of componenets.