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08 Imp is powered by air being released from balloons

I have an unusual sound coming from my 08 impreza 2.5l, automatic,non turbo (I ain’t rich or stupid with money). It has 97k miles on it and when I get up to around 30 mph I begin to hear a “screee!” noise. Much like air being released from a stretched end of a balloon. The sound only starts after about 5 minutes of driving and is consistent. The pitch slightly changes according to how much gas I apply. The sound seems to occur around shifting gears and of course stops once I go below 30 mph or am downshifting.

At this point I’m thinking it could be a hose or something in the transmission.

So I have replaced rotors and pads (twice), and just yesterday had the timing belt/ water pump, all the pulleys and accessory belts replaced. This model does not have an ac tensioner.

Did theis noise exist before you had the belts replaced? If it didn’t, take it back to them.

Sorry, yes the sound has been going on for many months before the belt replacement. I had thought it was a pulley on the timing belt and was hoping it would take care of it.

I would take it back to your mechanic and have him listen to it.

A shot in the dark, does the sound change when you turn off AC? If from the engine, it could be as simple as using belt dressing, or harder… a bearing in PS or alternator.

Sound comes from the front of the engine. I have applied belt dressing before the work that was performed and it continues to happen. Sound does not change when ac is on.
I have used the “manual” mode and it is hit or miss on the sound. I can have the car move around 30 mph and then switch gears from 3rd to 4th and it does interrupt the noise.

Power steering has occasionally groaned but I’m not seeing bubbles in the tank. Alternator is a possibility. I had a belt one time that was rubbing and spread belt dust all over the alternator. The dust could have caused the bearing inside to prematurely wear.

I don’t think dust would harm the alternator, but a tight belt
might. You could maybe pull the belts and spin and try to wobble
each pulley by hand. You may see a wobble in a pulley or some item
might seem loose or tight.

  Changing gears could be an indicator. You are dropping RPMs. Does

the noise happen at the same RPM in each gear? (You may not a
tach, though.) Maybe you could bring the engine RPM up around the
same, sitting in the drive. That sometimes works, sometimes not.

  If it's happening under load, it could be a bearing, I suppose,

but I’d assume it’d still howl in 4th. It’s not just in 3rd gear,

Im sorry for not replying sooner. I had written out a response but I guess I had not hit send.

So it occurs around 2.5 rpms. While holding that rpm I can push the car into neutral and the noise instantly stops. Putting it back into gear starts it again. Sitting in the driveway does nothing. Even after driving a while and getting the car heated up.

It seems that it starts on the 2nd, 3rd, and 4th gear.

Over this last weekend I found that the metal cooling lines for the transmission was slightly leaking. I thought for sure that this would be it. Replaced tje part and it did not silence the noise.

Did you check the transmission fluid level and add fluid if low?

Alright so the full story goes that I noted the leak and I did check the levels. They were holding steady at full. I went ahead and inspected the metal lines for damages and noted rust and must have opened the hole in the line bigger because I had a huge puddle at parking lot about 3 miles away from my house. A tow truck back home and new cooling lines, and a gallon of fluid later there are no more leaks and shifting is fine.

Edit - found a video of car making a noise that is extremely similar to mine. Only thing is that this noise does not occur in reverse and my noise is near constant at the 2k rpms

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