Whining noise when driving goes up and down with engine speed seems to whine more when going through gears. been there for a couple of months, took it to Mercedes dealers who could not put there finger on it

Ohh!
Merc can't find it,
They're usually pretty good.
I'd start with an isolation procedure,
i.e. taking the tension of the drive belt when it's running to see if that affects the noise.
If the noise goes away then it has to be something driven by the belt.
If it's still there it has to be something rotating at engine speed,
say the harmonic crankshaft pulley.
Process of elimination hopefully/

A piece of wood pressed against the ear makes a good stethoscope which can be placed at various points against the engine to localise the noise. Sounds like a noisy bearing on alternator or water pump or possibly the supercharger. Take care to keep clear of moving belts.