I agree with everything here, Steve. May I ask how you are defining Sacred Tradition and what you believe it contains (not everything it contains, just a general description of what it is)?
This is what the Church believes concerning Sacred Tradition:
*"77 “In order that the full and living Gospel might always be preserved in the Church the apostles left bishops as their successors. They gave them ‘their own position of teaching authority.’”35 Indeed, “the apostolic preaching, which is expressed in a special way in the inspired books, was to be preserved in a continuous line of succession until the end of time.”36 (861)
78 This living transmission, accomplished in the Holy Spirit, is called Tradition, since it is distinct from Sacred Scripture, though closely connected to it. Through Tradition, “the Church, in her doctrine, life, and worship perpetuates and transmits to every generation all that she herself is, all that she believes.”37 “The sayings of the holy Fathers are a witness to the life-giving presence of this Tradition, showing how its riches are poured out in the practice and life of the Church, in her belief and her prayer.”38 (174, 1124, 2651)
79 The Father’s self-communication made through his Word in the Holy Spirit, remains present and active in the Church: “God, who spoke in the past, continues to converse with the Spouse of his beloved Son. And the Holy Spirit, through whom the living voice of the Gospel rings out in the Church—and through her in the world—leads believers to the full truth, and makes the Word of Christ dwell in them in all its richness.”* (CCC par 77-79)
Look at it like this. The Church has always believed, for 2000 years, that it did not have the authority to ordain women. This has been the constant and consistent teaching of the Church. It was, however, never explicitly laid out in a definitive manner until St. Pope John Paul, II defined it as a doctrine of the Church to be held by all the faithful. And he only did this because the Apostolic teaching, always held by the Church, was being questioned by some within our own Church, as well as from outside. The Bible never explicitly states “Women shall not be ordained”, even though it contains plenty of examples that imply this. It is a truth that was held within the Tradition of the Church.
The doctrine of the Holy Trinity is the same. While it can be gleaned from the pages of Scripture, once it is already known and believed, the doctrine has always been part of the Sacred Tradition. I doubt there is anyone who, not knowing otherwise, could pick up the Bible and arrive at the Church’s definition of the doctrine of the Trinity, and its subsequent development.
Hope this helps.
Steve