Could the apostles add to Jesus' teaching after He ascended?

My understanding is that God revealed everything He wanted to reveal in the life and teachings of Jesus. Jesus then commanded the apostles to proclaim those teachings to the world, but He didn't give them authority to add anything to His teachings. If Jesus did not mention a topic in His life and teachings, the apostles were not given authority to speak on that topic--only to pass on what they had seen and heard. If we cannot find evidence that Jesus taught or acted on a given topic, that topic cannot become part of the Deposit of Faith--is that a correct assumption?