This happened with my wife's old car too and I always wondered what the cause of this was. It only happens when you're pushing on the gas pedal too. As soon as you let off the gas it goes away.

 

You have cancer. Naw just kidding. My first thought is wheel bearings but since its only happening under throttle I don't actually know.

 

Turbo building boost? Deer warning whistle? Power steering fluid low? Vacuum leak? Those are the only 4 things I can think of that really make sense.

 

Sounds like the turbo building boost to me. In 5th at 60, you're just about to the range where boost starts kicking in when you put your foot on it. Without throttle, the exhaust gasses aren't moving fast enough to make it audibly spool so once you step on it, it starts spooling and you hear it building up. Now if your wife's car did this too and her's wasn't turbo, then I don't know what to tell ya.

 

timing?

 

Look at the rpm @ 60, then hold the car in a lower gear, like 2nd, and see if the noise is there @ the same rpm.. Do the same for all gears.

 

It actually only happens in 5th starting pretty much at 60 and it fades away at about 70. I know it's not coming from the turbo. It's really weird. I can compare the sound to a constant beep like the Emergency Broadcast System beep when they are doing a test on the radio lol. The sound is not really loud or anything, it's just there and it's kind of annoying.

 

Ok. I did some experimenting today and realized that it's happening around 3-4k rpm in all gears. It's just more noticeable in fifth. You can't really hear it unless the windows are closed all the way. So maybe it's the turbo then? Would there still be turbo whine even if you're barely pressing the gas pedal?

 

Ok.. next is to hold 3-4k in neutral, both clutch in and out and try to hear it.. Maybe have someone else hold the gas while you listen under the hood....I'm trying to eliminate the tranny/clutch/flywheel. Happening in all gears at the same rpm eliminates the wheels, brakes, diffs, axles and driveshafts...

While your under the hood, listen to the pulley/belts, intake (both before and after the turbo), exhaust, etc...

 

O.k. It doesn't happen in neutral, only when under load it seems. I think with more load, the noise is a little louder. I think that's why it's more noticeable in fifth. I'd probably have to have the car hooked to a dyno in order to listen to where it's coming from under the hood.