Recently purchased a 98 Deville Concorse with 146 000miles, the car is in great shape. I have a noise problem when i start the car in the morning or when it is completely cold. The noise sounds like it is coming from the transmission or motor. It sounds like a rattling/ vibration noise. The noise can only be heard when you put it in drive and not neutral. The noise lasts for approximately 15minutes or until the car is warmed up. If anybody has any insights or may possibly know what the problem could be, could you please respond back.

thxs