Several owners (particularly 2000 / 2001 models) report a drivetrain noise and/or vibration that can be felt through the steering wheel at certain speeds.   Several D owners have called this the "wah-wah" noise.

We now have a solution for this problem, particularly if you have a 2000 or later model D, as reported by one of our members below:

I recently talked to John Claterbos from Freightliner and they tried to repair the wah-wah noise.  They tried twice to remedy the problem and finally on the 8th of October , success! They sent a service kit- 11-24531-000 which consists of dampeners that fit on either side of the rear end housing.  It was done under warranty and there is no more noise or vibration.   - Submitted by Arlen Heiser Member # 1753