At the company I work for we have a guy who we have used for years to service our fleet of cars and trucks he is a former Ford service man now at a Toyota dealership and he is quite good. I decided to have him look at my Mustang and give it a good listen as I really felt from day one when I picked it up the rear end had the dreded whine noise and I was right he felt it is quite excessive so off to the dealership it goes we shall see how it turns out.

2013 GT Track Pack, 3:73, Just turned 15,000 mi.

 

I also have some deceleration gear noise and that **** driveshaft clunk also. My 2014 just turned 1600 miles.

It was whisper quiet for the first 800 miles and now starting to get louder.

I think Ford has some Monkey assembling the rear diffs and driveshafts are probably made in some sweat shop overseas.

I run a shop and have assembled 100's of 8.8 diffs and am pretty sure backlash is too much or they're using cheap bearings that are settling in after build which leads to the slop. Then the backlash goes out the door. They may build them with .008-.012 but after the bearings break in probably opens up to .015-.020 and then happy whine!