When started truck will start clanking after it has run for about 10 seconds. When put in gear it will clank louder. The noise sounds like it is coming from under the engine / transmission area. There are no signs of fluid leaks and will make noise when stopped as well as when moving. Noise is louder when in gear. Truck is a 4 wheel drive also. Automatic transmission with push button 4 wheel / 2 wheel actuator.