Truck has 149,000. Used as a truck pulling single axle open and enclosed trailers about a farm. Rear end whines above 55. Never stops at 70. Goes away under a load. Worse if coasting. Quoted at $1,800-2,500 at a Ford dealer. More at a smaller dealer. Took it to a former dealer maintenance manager who has been on his own a dozen years. Quoted as not to exceed $1,000. Replaced both outer bearings, seals, inspected pinion and bearings and found ok. New fluid and special limited slip additive and with labor came in a $400. Had the tranny flushed correctly with new filter at same time. Total bill $519.00.

Now drove 907 miles to Florida at 70-75 MPH. Three people. Luggage. 20.6 MPG trip
Average with no noise. Message me if you need number for this shop in west central KY outside Owensboro. He is covered up for weeks, obvious why.