Thank you for responding so quickly. It has about 40000 miles on it.
I had a valve to chip off around the edges in the # 6 cylinder, for no apparent reason according to the mechanic . He said the 650 hp engine was known for this. Evidently some of that frag went into the turbo. Anyway, the Cummins mechanic came to my shop to do the repairs as the rear bathroom is over the engine and I had to demo it.