[renizzl23]

this is my first time posting so sorry if its in the wrong place, but i need help! i have a 2010 mazda 3i GT automatic with 38,000 miles on it. since about 18,000 miles or so, ive heard a squealing sound just before the car shifts up a gear, but its only when its between 1500 and 2000 rpms. if im being aggressive with the gas pedal, i dont notice it. i can also hear it, but just barely, just before it downshifts. i used to think it was from going up and down hills, and then maybe because the car is trying to be efficient and likes to stay in 5th gear when going up a hill at 35 mph. but i dont know anymore and im pretty sure my mechanic has given up on it. i take it to a Mazda dealership every time to get it serviced. his first thought was the belt, so he replaced that, and it was fine for about 500 miles and then it started up again. since then ive had the a/c compressor clutch and the belt tensioner replaced. along with a new belt each time. but its still making this noise. so far everything has been covered under warranty, but im worried that its going to cause something to break after my warranty is up. does anyone know anything about this squealing noise? has anyone else had this issue? please help because even my mechanic doesnt know whats going on