Rqh531

So I got the car about a year ago (automatic transmission) and occasionally when I come to an abrupt stop there is a 1-2 second delay after I press on the gas before the tires even attempt to roll and now when I put the vehicle in park I hear a continuous thumping sound that won't disappear unless I idle in neutral for a few seconds after parking. Thinking it could be the solenoid that controls the flow of fluid to/from torq converter but would love some input.