Q: When I change gears or when the car changes gears in motion, there is a loud thump. What do I do?

Hello. This is likely a transmission issue. Have you checked the level of the transmission fluid? When was the last time you had the transmission serviced? This includes having the fluid changed and having a new filter put in the fluid pan. Typically, technicians give a general visual inspection during this process and would be able to tell you if there were any major signs of damages. Signs of damages include metal shavings, burned oil, or low oil. Automatic transmissions are rather complicated.

If you feel uncomfortable performing this service, which is typical maintenance for the vehicle, then you should seek a mechanic and start there. If the transmission continues to act up after a fluid change, further inspection will need to be made. I recommend having a certified mechanic, such as one from YourMechanic, come to your location to perform a transmission fluid service.