Ah Robinson Brothers - they still open ?
bought cars from them a LONG time ago
Good that they got you going again!
39k miles is early it seems...
When I had my 6.7's in the 250 and 350 I spent LOT's of time on
Ford Truck Enthusiast and don't recall anyone reporting an issue - but mine only had 50K and 60k miles when I traded out of them last year.