One problem related to differential unit has been reported for the 1999 Mercedes Benz ML320. The most recently reported issues are listed below.
Truck shakes, shudders and makes thunking noise during even modestly sharp low speed turns (ie parking, etc) due to binding of differentials/driveline or brake/traction control malfunctions. Could lead to drivetrain or brake failure at highway speeds and subsequent accident. Dealer claims this is normal for this vehicle though it didn't occur ealier during ownership.