"his essential tenets have nothing to do with Jewish or any other traditions before him."
On the contrary, they have everything to do with it. When John writes about Jesus saying "I am" (8.58 and, more amusingly but less clearly because silly English translators have added in the word "He" that doesn't show up in the original, in 18.6), this is a direct reference to Exodus (3.14), in which "I am" is the name of God. Far from Jesus' declaring that the inner light within Himself was God, a departure from the Old Testament, Jesus identifies Himself with the selfsame God who fills the Old Testament. Much of what Jesus says and does in John 13-17 (especially 17) follows in this vein as well.
As another example, when He was asked what the greatest commandment was, He didn't come up with something new or try to explain that the commands from the Old Testament weren't really what He was dealing with. What Jesus did was to draw a line out of Deuteronomy -- one that puts the "God of Laws" at the center of His teaching: "Hear, O Israel! The Lord our God is one Lord; and you shall love the Lord your God with all your heart, and with all your soul, and with all your mind, and with all your strength."
Jesus also cared rather deeply about Old Testament history (particularly the prophets whom God had sent to Israel) and brought it up to make his case against the contemporary rulers and teachers:
"Woe to you, scribes and Pharisees, hypocrites! For you build the tombs of the prophets and adorn the monuments of the righteous, and say, ‘If we had been living in the days of our fathers, we would not have been partners with them in shedding the blood of the prophets.’ ... Therefore, behold, I am sending you prophets and wise men and scribes; some of them you will kill and crucify, and some of them you will scourge in your synagogues, and persecute from city to city, so that upon you may fall the guilt of all the righteous blood shed on earth, from the blood of righteous Abel to the blood of Zechariah, the son of Berechiah, whom you murdered between the temple and the altar" (Matthew 23.30-31,34-35)