tranmission help subaru wrx 2004

You are correct. Not likely to be a throw out bearing unless you hear the noise while depressing the clutch. It is not supposed to be used when not pressing the clutch petal. Most likely differential or transmission noise. If you are a DIY, jack up one of the front wheels on a level surface (don’t get under it} and with it in gear, move the wheel that is off the ground by hand and check for play or noise.