Hi all,

Just did a search for an odd unpleasant humming that has begun to occur at 30 - 35 mph on my 1999 C280. Seems that others have experienced this due to failure to change the differential oil regularly.

Two questions:

1. What oil or oil+additive do you recommend to service the differential on a car with 144K miles?

2. Is there any way to eliminate the humming or will I have to live with it from now on?