My observations on TRAN and INDU relationship so far:
If TRAN breakout, but INDU did not, INDU will follow and breakout. The inverse is not true.
If INDU breakout (like today), but TRAN is going the opposite, then the trend of INDU is not as strong as it looks like, and it should go the way TRAN goes.
If INDU breakout, but TRAN is going flat, INDU doesn't need to follow TRAN, and TRAN doesn't need to follow INDU. But be aware that INDU's breakout could be a fake one.