yep can almost 100% confirm the whistling noise is transmission related. Did a take off with my head out the window and u can definitely hear the noise from under the car.
The whole "it does it more when the car is at temp" is probably because when its warm the fluid gets thinner????
It's got the heavy duty tow pack and the previous owner used it to occasionally tow a caravan (probably in eco mode too), so that's probably what wore it out in the first place.
I've been driving it around in power mode, still get the whistle on the takeoff.
Hopefully an oil change, filter and maybe some additives will shut it up.
Lucky for me it's an early EF so it's got the dipstick.
Edit: just saw this on another post:
"A blocked BTR auto trans filter, can also make a whistling noise on acceleration -
the transmission oil pump becomes noisy like that, as it strains to move fluid around."
destructo got a reaction from gerg in whistly / wheezy sound ef falcon