Harmonic Drivetrain Noise
Okay, I've used the search tool and found some good info, but nothing that describes my problem exactly.
I think I've eliminated the wheels/tires as culprits for this strange highway noise I'm getting at speed. The car is an '84 300D with 230K miles. I'm pretty sure it's something in the driveline--perhaps a driveshaft out of balance. The sound is like:
wwwWWWOOOWWWwww...wwwWWWOOOWWWwww (ad nauseum)
...in other words, it's not constant, but fluctuates harmonically. Could it be worn flex discs? A fatigued tranny mount (deviating the angle of the shaft)? Out-of-balance driveshaft?
I've managed to get this car fairly quiet at highway speeds, and now this noise is particularly apparent.
1995 E300 Diesel (Die Blau Frau)