any suggestions for a diefiant 4 year old. he only does it at school?

It sounds like he's just having trouble to the new school and daycare. It's normal for young children to become quite upset over these types of changes.

If I were you I would do two things: sit down with his teacher to discuss some ways for both of you to handle this, and talk to your son about how this is affecting him. Kids throw tantrums and act out when they don't know the right words to express how they're feeling. Talk to your son, ask him what he likes about his new school and find out how he's feeling about the new changes. Explain to him why he had to change schools and talk up the new one, tell him all the good things about it. Once he's a little more enthusiastic about his new school explain how to behave properly there.