It seems like the live action movies will continue its relationship with General Motors. According to MLive, a Transformers 4 crew is scouting GM's Grand Blanc Weld Tool Center as a backdrop for filming in Flint, Michigan. Work at the tool center will end in July, which would probably make filming a movie a lot easier since nothing would be going on there. General Motors Co. spokesperson Robert Wheeler has stated that nothing has been committed to by either side yet and this type of thing is a long process to work out.
This location could be used for multiple reasons. One could be the workplace for Mark Wahlberg's character. Another could possibly be a race shop for Jack Reynor's character, who is a race car driver. They could also decorate the place to look completely different so that it works as something else.
The Transformers trilogy has used many General Motors cars, including the Camaro, Solstice, Corvette, Impala, Hummer, Topkick, Suburban, Beat, Trax, and Volt. It seems fitting that they will still continue the partnership.
Photo from Flint Journal