There is actually a long drawn out story to this, but in a nutshell, no Ford has no ownership. Cummins has some stock in all of the big 3, and Dodge and Cummins have a contract for engines for light duty trucks only. This is why the 5.9 Cumminsis available in F650 and up trucks. Different segment.
So, with that contract in place, unlikely that GM will be outsourcing their diesel engines, and like posted, the Dmax has been an excellent motor for them. There was alot of suspicion from non GM loyalists, but the motor design has proven itself to work, and work well. Bottom line, if it ain't broke they won't fix it. Cheaper that way.
Besides, if GM went to Cummins where would we all go to pick on each other about trucks?
Boy the Ford guys would be pissed!
