In a recent interview involving his new movie Journey 2, Dwayne Johnson had something interesting to say about TF4 and Bay while talking about another movie he will be starring in, Pain and Gain, which will be directed by Michael Bay. This could just be Johnson speculating, but you never know.
"It's an awesome project called Pain and Gain. It's been with Michael Bay for some time now. The goal will be to shoot it next year. Sure. Because, I know, he has Transformers to make. Obviously. That juggernaut. I can't wait for that."