Q: What can be causing vibrations to my vehicle - the rear engine mount or the exhaust pipe?

Hi Ben goodday how are you. Can an engine mount be bad even if when you had it removed and inspected the rubber and everything was intact and Smooth.i replaced all 3engine mount except the rear mount also I had my exhaust muffler replaced but the one used to replace it is skittle bit smaller the the previous one.although the vibrations problems were there before and after I replaced it the exhaust beats against the body of my car and the vibrations travels all the way from the engine to the rear when am at a stop but once I put it in neutral the vibrations really reduced. Was told because the muffler is a little smaller it's cause the vibrations but the only time it got better was after 3mounts were replaced. So what I want to know is the rear mount looks fine so could it be the exhaust that is making the remaining vibrations occur or is it that some things is still wrong with the position of the engine.and when you change gears should there be a little movement in engine or non at all

My car has 76200 miles.
My car has an automatic transmission.