Originally Posted by kstanf150
Ford is the only HD truck brand that build it own engine and transmission in house
Engine-wise, that's entirely due to the fiasco with International for the VT365/6.0L Powerstroke and the MF7/6.4L.
One cannot, while keeping a straight face, take a swipe at RAM for continuing to use the excellent Cummins engines, that would be utterly stupid.
Transmission-wise, Ford has, since the 4R100, made some absolutely excellent transmissions that were, to put it kindly, mated to some less than perfect engines. The termination of the relationship with International led to the creation of the Scorpion engine which has, aside from the Bosch pump issues, been, AFAIK, quite good. Ford has an extremely competent engineering team and if left to their own devices can produce some fantastic equipment but they are certainly not infallible.
Remember that the Duramax came of age during a period where Ford was selling the 6.0L PSD. Mating it to an Allison transmission also was a pretty good move for GM, capitalizing on that name, like Dodge always did with Cummins. And of course Allison was a GM brand at the time.