Just to add minor details...

The Chevy Duramax is an Isuzu.
The 6.0 Ford is a Navistar/International.

6.0 Fords were available in 2003; I belive they did the 7.3 for 4 months or so, then switched over. My '03 Excursion has a 6.0, plus the new 5-speed TorqShift tranny.

Haven't heard anyting bad about that particular tranny yet....

Jarrod