Squeal During Acceleration

During acceleration my car makes a high pitched squeal that seems to come from the front end of the car. It only happens when the car is in gear, not when I rev the engine in park or neutral. The dealership said that they need to replace a part on the exhaust. I don't doubt that they found an exhaust part that may need to be replaced, but does it make sense that it would cause a high pitched squeal under the conditions that I mentioned? Please provide as much detail in the response as possible. I mentioned under another post that I have the same problem, but I would say it is almost like a loud whistling sound. Happens when RPM approaches or above 2000. If I accelerate slowly it is barely or not at all audible. Very annoying otherwise. I would like to know what could be causing this as well.

Thanks.