Cummins=CAT motors, and they're more reliable then the chevy motor.
Best parts from each american diesel truck:
Ford=body
Chevy= Drivetrain/axles etc
Dodge= Motor
No.
Cummins is its own company, has nothing to do with cat or chrysler. Cummins has a deal with dodge to exclusively use cummins in RAM (not with ford or Chevy). Kind of like how Allison has a contract with GM to only use their transmissions in the light duty market.
Cummins has been around for around 80 years. One of the best diesels on the market. Easiest to maintain and modify too, not o mention cheapest to modify.
Also, ford bodies are shit. They rot worse than Chevys.
Ford is good for their axles. That's it. And that's only cause they use DANA axles.
Dodge is only good for the Cummins that comes in it. Pretty much garbage everywhere else.
Chevy has the nicest interior by far. Best driving truck in my opinion. But, they rot too, and have quirks because of their IFS that dodge and ford don't use.
By the way, CUMMINS IS NOT OWNED BY DODGE OR CAT