The Ibrox chief executive has thrown his weight behind McCoist, despite the Gers gaffer handing his shares to the Calderwood Loyal, who are likely to vote against the board at Thursday's AGM.
McCoist could be left in a difficult position if the current hierarchy fight off a challenge from four board hopefuls.
But Rangers Supporters Trust chairman Dinnie insists the other directors - chairman David Somers, finance director Brian Stockbridge, James Easdale and Norman Crighton - must follow the CEO's lead.
He said: "It is excellent news that Wallace is backing the manager. However, we have seen the situation of one board member being outvoted in all major decisions twice before.
"Our members' AGM voting poll shows a complete lack of trust in the current board besides Wallace.
"We would love to hear the remaining members of the current board say they are 100% behind our manager at Thursday's AGM."