FYI: A 1995 F250 wouuld have a 7.3 PSD, not a 7.0. The older non-turbo PSD before the 7.3L Non-turbo were 6.9L.
What serious repairs issues are you about to face? Assuming its an automatic, automatic transmissions in pick-ups seem to be a weak point across the brands (excess heat when hauling/towing/off-roading usually.) . The earlier turbo PSD have some issues where the turbocharger mounts, and the downpipes come apart with age. Diesel engines (assuming properly maintained) last well into the 400k+ mark. And usually (also assuming properly maintained.) the differentials hold up well too.
Why limit yourself to a Duramax? Whats wrong with the newer PowerStrokes or the Cummins series Dodges? Just wondering.