2004 7th Gen Euro cruising noises

[sodhi90]

yep i have an 03 5AT Euro and i get the noise on the highway when the car is in 5th gear , only when accelerating and yes it goes away when i lift of the pedal, its like a whining noise. No idea what it is but it annoys me lol

[Harbournet]

After some thought about it....only after certain speed...the torque converter locks up in 5th, like in any auto. Therefore this sounds like it must be a noise coming from the torque converter somewhere...? Sound logic?
The car doesn't make noise at any other time, during accelerating or slowing down...or after it kicks back a gear or 2 to overtake. Must be something to do with the final drive after the converter locks up.

Anyone with some idea of how auto's work - feel free to add your 2 cents.