The junk truck we saw earlier in the filming could be alpha Trion trying to warn the autobots about a new threat which would,be the creators and Megatron somehow is working for the creators and kills the junk truck.
That's plausible. The junk truck probably does get killed early on. I'm interested on why we haven't seen any other Decepticons except for Barricade on set since June. Onslaught hasn't been seen, the motorcycle, junk truck, Wagon, none of them.... As for Alpha Trion, I hope they'd give him a bigger role instead of the junk truck.
The junk truck could be a junkion but as post above states that it been a movie then it could be any character he chooses. I honestly don't think it would be alpha trion as a junk trunk would not suit him. Say that though he was an inventor/creator in g1 so with all that junk/parts he could create things from the junk. That could indicate him only time will tell I suppose
I doubt that's Alpha Trion, at least now that Hasbro has more control over the movies. To me; junk truck + junk parts = Junkion/WrekGar.
