JimQ

I have a 2001 Lumina (daily driver) that has apporximately 149000 miles on it. Last week I heard a thud sound from under the car while driving it. Shortly after that I started hearing a whinning noise. I was driving in OD at about 50 mph when I heard the thud, the wihinning gets louder as speed increases. If I shift from OD to D the noise goes away. Any idea what to look at or for as far as repairs go? Thanks in advance for any help.