It is very important that you know that the XBox 360 DVD Drives ARE NOT interchangeable. The DVD Drives are married to the mother board. So if you are going to be purchasing a new drive or parts for XBox 360 DVD drive you must know what type of DVD drive you currently have. You can determine the drive type by the DVD caddie or by the wire type under the faceplate.
Original (Fat) XBox 360, Drive ID by Wire Color Under Hidden Under the Faceplate
Original (Fat) XBox 360, Drive ID by DVD Caddie Type
XBox 360 Slim DVD Drive Identifcation by DVD Caddie Type