My transmission went and was replaced under warranty this past week through a factory service center. I test drove the car AC on, highway and local about 20 minutes, no issues. Signed off on repair, left the service center. The sun was down so I turned off the AC. Stopped at first light, RPM started to race in D, put into N, continued to race, drove back, shifting seemed "off."

Factory Service Center said car needed a "crank sensor", had it replaced. Took car on test drive without rep; highway and local, about 20 minutes in, during the local portion, the transmission started to make a high pitched wine, when shifting between 1st and 2nd. Stopped the car, put in N, revved the engine, sound discontinued.

Pulled up to a light, car stalled, and had a sweet smelling order coming through vents. No over heating. Turned car back on, RPM erratic, started to drive, shifting was very off. RPM started to rev without foot on gas, put car in N, coasting at 4K RPM. Got another mile down the road, and it continued to do the same, problem increasing. Had service center come pick me up and drive the car back on their own, car was fine at first, but as soon as it gets warm, the symptoms start again.

The car did not do anything like this before I brought it in for the transmission. When they swapped the transmission, they also replaced the timing and drive belts, redid all the coolant hoses and clamps, flushed the breaks, power steering, and oil change. About a month ago I had the thermostat replaced do to overheating.

Just want to know what might actually be going on. I don't know a whole lot about cars, and mechanics seem hesitant to talk to a woman like a human. Car hasn't had any major issues until now.

Thanks for your help. I just want to feel prepared and not get screwed over.