There are actually quite a few differences between John and the Synoptic Gospels. To begin, there is quite a bit material not in John that is actually included in Matthew, Mark, and Luke. This should be taken to mean that the events did not happen, however, as historicity has proven most of them to be true. This includes the transfiguration of Jesus, Jesus’ temptation, and the Lord’s Supper. John also does not make any mention of Jesus being able to cast out demons. Some other major differences include:
• Material including in John’s gospel not in the other gospels
• Different references to the length of the public ministry of Jesus
• A different literary point of view
• John uses symbolism and double meanings that are not utilized by the other