Hey ladies and gents. I drive a 2004 chrysler crossfire that's a 6 speed. When I put it in 1st gear and even shift in 2nd gear. I hear and feel a thumping sound. But if I let off the gas and then reapply pressure it goes away. The idiot shop I bought it from said they didn't know what it was. So I know how a lot of you have had your cars and are a little more experienced in what it could be. I'm guessing because it's coming from the rear. Maybe a independent drive axle on one side. Any help will be appreciated. Thank you so much.