Differential Unit problems of the 2018 Ford Mustang

Purchased a brand new 2018 Ford Mustang ecoboost premium 10-speed with performance package July 21, 2018 with 9 miles. Took car to the dealership November 2018 at 2,600 miles with a popping feeling and sound as well as an unsafe loose feeling in the rear end. This happened any time driving over uneven surfaces, turning curves and accelerating. They replaced the shock absorber after the car was in the shop 11 days. In January 2019 I took the car back to the dealership with 3,893 miles. The car was still making a grinding, popping sound in the rear end as well as the front end. The car also still felt loose as if was going to lock up while driving. The popping, grinding happened when pulling out of a driveway or parking space as well as sharp turning of the wheels. The loose feeling was going around curves, left or right turning from a stop light as well as accelerating from a stop. The car also felt as though it was not shifting properly. The dealership replaced the fluid in the rear end and after 8 days they said the rear differential needed to be replaced. It has since been 8 more days in the shop with no word. I feel this car is unsafe as it is such a new car, has been babied from the first day purchased. The fact that it has been in the shop twice almost 30 days of its life, under 4,000 miles and having the rear differential replaced shows there is something seriously wrong with this car. All this being reported to carfax has drastically reduced the value of my car since it does not report it as factory defect but rather possible abuse. I do not know if this is just my car or a safety issue from the factory. I asked the service manager if it was possible for the car to lock up on the highway and he confirmed it was definitely a possibility. At this point I am afraid to drive this car not knowing what else could go wrong with it.