Possibly torque converter failure

Came here to say a new car lmao

Don’t drive it home 700 miles go straight to a mechanic… if you keep going that pad will fall out or grind away causing the caliper piston to come out and then you have a very fast fluid leak meaning you instantly loose all brakes it would be a danger to you and everyone around especially at high speeds on highways

How many miles and year make model

Probably a leaf or something fell out of the old filter without them realizing