The Cummins powerplant is one of two options for the moment, the other being a hybrid powertrain. If the oil-burner got the thumbs-up, Toyota would follow the recent example of Nissan, which announced it would put a Cummins turbodiesel into its 2015 Titan. While the two Japanese companies make a closer comparison since they're both talking about Cummins applications in light-duty trucks, if it happens, it could be seen as further diluting the once-exclusive tie-up that Ram trucks has had with Cummins even though Ram has used Cummins in its heavy-duty truck.
Toyota hasn't said when it will decide on which direction to take, but either will be a move for the better in the view of segment watchers; PickupTrucks.com said the first of its top-five fixes for the Tundra would be a better engine, perhaps a diesel-electric hybrid from Toyota's Hino unit. Cummins told Edmunds it can supply a second manufacturer with the 5.0-liter diesel that Nissan will be using, so we wouldn't be surprised to see it end up in a Toyota or somewhere else.