Let's see if we can figure this one out...... I have a 1985 300D turbo with 249,000 miles on it. About 1.5 hours into any long trip, a weird flapping sound occurs in the rear from what I can make out. Nobody is ever with me to experience it unfortunately. The frequency of the noise seems to change with rpm. If I park it and rev the engine I don't hear anything. If I turn the car off, quickly inspect to make sure I'm not dragging anything, restart, and continue on my way.... the noise is gone and doesn't occur again for another 1.5 hours! Ant suggestions?????
One more thing....... I notice that sometimes when I brake, I hear a thud noise in the rear. I'm assuming it's some sort of bushing after reading through some other threads. Could this be related?