1996 Chrysler Sebring Conv

I recently took my car in for transmiision leak but they wanted too much to repair it. When I picked it up, it made a loud shrill noise when I started it but then went away after it ran. It never did that before. It is almost like there is a missing inspection cover for the trans which I don’t believe it has one. I was wondering if it could be a bad torque converter but the noise does go away after it starts.