Rear end noise
 

My wife has a 2010 F150 Supercrew with 77000 miles and I have noticed a Howling noise coming from the rear end when the truck is coasting at hwy speeds, going down hills or when you let off the gas and start coasting. Has anyone else had this issues. I thought it was the tires at first because they were due for replacement, got new tires noise still there. Any thoughts on this?

My 2000 Expedition did the same exact thing at about the same mileage. It howled while coasting but not under power. It turned out to be the pinion seal and bearings in the rear end. I spent $750 bucks to fix it it. After the fix I went for 130K trouble free miles with the new seal and new bearings.

Had the same problem on a 05 150. Solution was pinion seal and bearings. $900 in 09.