Hi, first time on the forum. I have a 750 with 18,340 miles. I just changed the oil with Amsoil 10-40 and Amsoil filter. Filled to correct level. While warming up the engine, it made rattling noise for a bit then quieted down pretty quick. The oil light was not on so it had pressure. I prefilled the oil filter, which I had never done before. After changing the oil and filter, started it up...engine noise did not quit and oil light stays on. It doesn't smoke. Previously I thought the noise was from CCT, but now I think I've had a low oil pressure issue for a while, but the light hasn't come on. Could it be an oil pump, or are the bearings worn out?