yo Chris;
HAVE YOU PULLED the shaft to inspect needle bearing,snap ring inside carrier & differential side gear splines, spindle & wheel bearing torque, etc.?
ANY Noise, Vibration and Harshness?
Inspection and Verification
Source: by Ford
Bearing rumble sounds like marbles being tumbled. This condition is usually caused by a malfunctioning wheel bearing. The lower pitch is the result of wheel bearings turning at only about one-third of driveshaft speed. Wheel bearing noise also may be high-pitched, similar to gear noise, but will be evident in all four driving modes.
I use this info to just help diagnose:
Vibration, Failed Bearings; "...Vibrations caused by bearings usually can be heard and felt. Bearings are usually under a load of some kind. Changing the load on the bearing should change the sound or amplitude of the vibration. A front wheel bearing's load changes when the steering wheel is turned back and forth while driving..."
Source: by
http://www.vibratesoftware.com/html_help/2011/Diagnosis/Other_Causes_of_Vibrations.htm#Thermostatic
Load the left front and left rear wheel bearings by turn sharply to the right while driving. Listen for a noise change.
Load the right front and right rear wheel bearings by turn sharply to the left while driving. Listen for a noise change.
Load the front pinion bearing and the left differential side bearing by accelerating while driving. Listen for a noise change.
Load the rear pinion bearing and the right differential side bearing by decelerating while driving. Listen for a noise change
Bearings - If the bearing noise was louder while turning the vehicle right on the road test, inspect the bearings on the left side of the vehicle for roughness. Replace as necessary.
Bearings - If the bearing noise was louder while turning the vehicle left on the road test, inspect the bearings on the right side of the vehicle for roughness. Replace as necessary.
Bearings or Gears -If the bearing noise was louder while accelerating or decelerating vehicle on the road test, you probably have drive axle problems. click here to diagnose.
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96 Bronco-F-Series Workshop Manual (PARTIAL)
Same as most earlier years exc. for OBD II in 96, 4WABS (93-96); ABS (87-92); Air Bag (94-96); 3 ***** Automatic Locking Hubs (Built from May 95 through 96); Spark Plug Wire Routing & Firing Order (The firing order for 1987-1993 5.0Ls is 1-5-4-2-6-3-7-8. The firing order for 1994 5.0Ls & all 5.8Ls is 1-3-7-2-6-5-4-8.); and a few other items
http://www.diesel-dave.com/vehic/manual/stj/stjleft.htm
see
http://www.diesel-dave.com/vehic/manual/stj/stj53a09.htm