Transmission Fluid Leaking problems of the 2012 Chevrolet Sonic

First problem started when radio remained on after key removed from ignition. Radio would turn on and off when car was off and drained newly replaced battery. Advised to remove fuse as temporary fix. Car was also losing power when highway driving (up to 70 mph). I don't speed, but car struggled to go above 70 mph. Thought I smelled something burning, had radiator checked, oil changed, fluids added at beginning of October. Three weeks later on city street, slowing for traffic when car lost power. When traffic started moving, car continued to slow to complete stop in the street despite stepping on gas. Waited 25 minutes for tow, but when tow driver came, car was able to start and move. Less than an hour later, the problem happened again and car was towed. At mechanic, computer codes indicated low/no transmission fluid (even though fluid was added at oil change only three weeks prior). No evidence of leaks. Mechanic added fluid and went for ride on suburban back road, car lost power after 10 minutes. He had to wait approx 20 minutes for car to move again. He drained transmission fluid and found metallic bits, and says transmission would likely need replacing. Car has fairly low mileage �54k miles� and has been properly maintained. Also car was previously serviced because key was stuck in ignition.

12/23/16, I purchased a 2012 Chevrolet Sonic. 4/6/17, I was at a traffic light when smoke come in the vents from the hood of the car. I called onstar & to run a diagnostic. The diagnostic didn't return any information & I contacted the dealer & took the vehicle for service on 4/9/17. I was told the thermostat housing was leaking and caused the smoking. The coolant system was flushed & filled & a gm oil, lube, filter change was done. The vehicle was ready for pick on 4/19/17. A few weeks later the car was smoking again. I called the dealer, I was told it was probably just fluid on the engine. The car continued to smoke periodically. 6/7/17, there was a large pool of oil under the car, I took the car to a local shop. They said that the oil had been overfilled & that it blew a seal. I called the dealer, I was told they did not overfill the oil & made another service appointment. I was told again there was a problem with the coolant system & the oil & that was the reason for the smoking. Repairs completed 7/10/17. 9/27/17, while driving the check engine light came on, so I called onstar for a diagnostic & they gave me an error code p0299. They told me that it was an airflow problem. I called the dealer & asked for the service manager & gave her the error code. She said there was a problem with the turbo & that I needed to bring the vehicle in. I took the car to them 10/3/17. 10/4/17, the service department called me & told me that the turbo on the car was bad. The repairs were completed on 10/12/17. 10/13/17 the car overheated. The vehicle was leaking coolant in two places. I took it to a different dealer & they said the t-joint in the coolant system was leaking. The repairs were completed on 10/18/17. 11/3/17 an email from on-star said there was an engine problem. I contacted on-star for a diagnostic & they said something is wrong with the coolant system.