on my 300E 1988 the 2 rubber bushings that hold the back of the rear diff are shot. It makes a clunk when going into drive or park,also when I hit the kick down while accelerating or taking my foot out of it during acceleration it is very bad!
Jack up the back of thre car and release the park brake but leave the trans in park so the drive shaft does not turn.have someone turn one of the tires back and forth while watching the bushings to see if the diff jumps up and down you will know right away if they are shot
