Hello, my car is a S350, when driving it will “go out of gear” and it seems like it’s on Neutral, need to pull over and turn the car off and on again. When I pull over and put it in P, it will get stuck on P and not go into D unless it is turned off and on. After this happening it will display the Check Engine light. It sometimes does it when stopped in traffic as well.

i would appreciate it if anyone that knows anything about this specific transmission could help! Thanks.

Sounds like it could be a Conductor Plate issue or low transmission fluid level. My S65 AMG transmission went crazy, I replaced the conductor plate and it was a new car! Hope this helps.