There is a continuous whining noise that seems to be coming from my ML430 engine with 84K miles. Noise always present when engine on and follows the RPM of the engine. The noise is evidently annoying enough to some people that I get asked "what is wrong with your vehicle", however, when at the Mercedes dealership for non-related repairs they said nothing of the noise? I am wondering if the noise is from the timing chain or valvetrain area. Good oil change history with Mobil 1.

Noise is not from anything that the serpentine belt runs because the noise was present with the belt removed. This alleviates many things; waterpump, power steering, alternator, fan, belt tensioner, idler pulley, compressor pully.

I guess the transmission is a possibility but noise seems more forward but could be my imagination. I have had a Chrysler van that made a similar noise and it turned out to be a bad transmission.

Any similar cases out there and the solution?

Problem transmission pump would do this (don't ask how I know... )

Listen to the tranny's bell housing under the car to confirm my supposition.

__________________
Eric

1991 560SEL-Euro (214,000 miles)
1989 420SEL (Retired from daily use at 325,000 miles; Use as donor vehicle)