Hi and thanks for using 2CarPros.
Adding oil, whether it is too much or too little, won't shut the engine. On some vehicles, if oil pressure is lost, it will shut the engine down to prevent damage. However, that is not relevant with this model.
As far as the speedometer, you should have the computer scanned to determine if there is an issue with one of the speed sensors. Chances are it is the vehicle speed sensor (VSS).
Here are simple directions for testing VSS. Picture 3 shows general location, and picture 2 shows how it is tested and what to look for. Picture 1 shows location on the transmission.
Let me know if this helps.
Images (Click to enlarge)
Monday, November 26th, 2018 AT 5:18 PM