I have a 1992 500 SL with 110,000 miles. When I first start the car and the engine is cold, I will occasionally hear a high pitched whining sound when I depress the accelerator, even with the transmission in neutral. This sound seems to come from the front of the engine.
After the engine has warmed up I will still occasionally hear the same high pitched whining sound but only when the transmission shifts gears and the sound seems to be coming from the transmission. Any ideas as to cause?