I have a 2009 GT with 5 spd manual. About 8 months ago a noise developed in the rear end. Noticed it while turning at slow speed such as turning into a parking space in a shopping center or into my driveway. Sounded like a waa waa waa to a warble warble as the wheels turned slowly. I also had a lot of clunking when shifting. Took it to my local shop and was told may need ring and pinion. I wanted to upgrade the 3:31 gears for a few years so I went to a Mustang rebuild shop in So Florida. The owner there said to change the driveshaft to a one piece aluminum and change axle bearings. I told him I wanted to upgrade the gears to 3:73. He said the clunking was from the driveshaft. Got this all done and car ran great. No more clunking and no noises. Within a week the noise came back when turning. A couple guys said it may be in the traction-lok differential. Can’t understand why it went away then came back. If that is the case have to pull rear apart to replace diff? Any suggestions???