I have a 1997 C180 in Australia and the auto is starting to show odd signs of wear/tear or breakdown. It makes a whining sound as I drive off in the lower gears and disappears in the higer gears. Does this all the time now. I also have the 1994 C180 with the old 4 speed auto which is not electronic and this one still makes no sounds at all although it has not much grunt, much less than the 1997 model of same engine size. Has the trans gone south or do I need new auto fluids? Will new trans fluid and filter solve this or is worse news coming like gears gone or other parts need replacing. Its not wheel bearings otherwise the sound will be there all the time not related to speed. Can there be other problems from the drivetrain causing this sound? The universal joints? Please help, thanks. Just for info, the 1997 has 226,000kms and the 1994 has 206,000kms on the clocks.

Transmissions whine 101
A whine in park or neutral that increases with RPM could be a plugged filer or a worn oil pump. If you hear the whine when in drive at a stop it could be a bad torque converter turbine. A planetary whine will change pitch or disappears when the transmission shifts .a planetary whine will also disappears in direct drive.

With that mileage it sounds like planetary.

Thanks C32, what do you mean by planetary(spinning pieces of metal?) whine? Do you mean in the gearbox or in the universal joints? There is no noise really in gear at stop except you can still feel the push from behind, a bit of soft rattle with my foot on the brakes. If I free the gears, there is no such experience. Therefore at stop, foot on the brakes, the gears still in drive shouldn't the gears be disengaged or just on hold? One tech said the rattle is from the drive belt tensioner needs replacing. If so, why is it silent when the gears is in Neutral and not in Drive? I have to get to the bottom of this soon before worse things come along, cheers.