2001 Taurus vulcan engine and AX4N tranny 60kmi. I have heard this before, and it wasn't good. My old 1994 probe made this similar noise and then the tranny ground itself into a pulp ( Ford remanufactured tranny w/ only 40kmi). At idle its faint, but when the engine speed goes up ( driving or not) there is a high pitched whistle noise. It is getting louder. Is there something I can look at before I take it to the dealer. :confused: Fluid and filter were changed 10kmi ago, and the level is fine. Still Red in color. Thanks for any ideas.

It is possible the whistling is coming from the engine. Two things that aren't at all common just popped into my mind when I read your post. The first was every Ford tech's favorite culprit...the IAC. They make more of a hoot noise than a hight pitched whistle. The second, which I've only seen a couple times is a plugged PCV. If the PCV valve plugs, pressure can build up in the engine and it escapes around the crank seal, causing a high pitched whistling at the front bottom of the engine. Anyhow, neither are common but both are worth looking into before a trip to the dealer. Good luck with it.

Thanks for the info, i'll take a look today.

Well there is good vacuum at the PCV valve, and the IAC is pretty quiet. The noise seems to be comming from the serpentine belt area. Could something on that side be causing this ( alternator, pullys, A/c, water pump??) Thanks.