I was applying online on GM's internal posting site as I was already an employee. I heard from my (now) boss about scheduling a phone interview with a lateral manager. The manager asked me about some situations I'd been in at work and how I'd handled things. It was a very relaxed conversation. They mostly just want your honesty and see how you react to difficult situations. About a week later I was contacted to go interview with my current boss. He asked more behavioral questions and a few things about my knowledge of the role I was applying to. Then I spoke with my director and she asked more behavioral questions. These interviews are not hard so long as you prepare a few things to say regarding situations you've been through in the workplace.