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.