I have 1985 300D auto trans. I hear a clunk sound when I shift into neutral on my way to drive. I also notice from the rear of the car that if I tap the pedal during neutral or park (if the parking pin isn't engaged yet) the driveshaft rotates clockwise and lightly bangs against the inside of the diff. I have clunk noises everytime i downshift. I replaced trans mount, carrier, and diff mount. I hear a clunk sound on the highway when i let off and on the pedal too...

Car has 145k on it.