John 21: (We'll be using the KJV today to keep things on even footing): "And there are also many other things which Jesus did, the which, if they should be written every one, I suppose that even the world itself could not contain the books that should be written. Amen."
The Bible Itself declares that it doesn't contain everything.
But the Bible says it contains everything pertinent to our Salvation...It was written so that we can know we have eternal life, right now...
There apparently is a reason Jesus felt we had enough information with what He gave us...No where did Jesus suggest that some group later on would be able to add to what Jesus did and certainly not to any thing that He taught...
And the fact that you guys don't have any thing at all in the way of 'handed down tradition' pretty much proves nothing was left that Jesus intended we should know...