When I got rid of the old girl I had 344,000 on my Ford 95 diesel with only oil changes, new tires and 2 serpentine belts.
I read some blog where a guy posted that he had gone over a million miles in his Dodge diesel pickup. There must be a few of those around, with their Cummins engines. The 7.3 Fords seem to have the same kind of reputation.