Toyota is being mighty tight-lipped, but the rumor is, they'll be teaming up with Cummins. BUT ... I heard the same thing 2-3 years ago, so who knows? The last I heard was the 2020 diesel Tundra was scheduled to "possibly" hit the U.S. market around the middle of this year. I'll believe it when I see it. Toyota usually does so much testing to make sure there are no bugs that they are usually behind the competition. But I'll take reliability over "the first to hit the market" any day.