Death Rattle?

Jake bought an 02 Ram with the 360 in it a couple of years ago. Had 165k on it when he bought it. Previous owner claims to have only used Castrol oil in it. Still had good pressure, but was using 1.5 quarts between 5k mile oil changes. At 180k, Jake switched to Rotella T. He now has 230k on it, it uses a half quart less oil between changes and it is quieter at start up.