As the change is before the required six consecutive events the Monegasque will take a 5-place penalty for tomorrow's Austrian Grand Prix.
"5 places penalty because of a gearbox change," tweeted the youngster ahead of Q1. "It's fine, we'll push to get the best result anyway."
Having posted the tenth quickest time earlier, despite the penalty the youngster is still expected to challenge for a place in Q3 this afternoon.
Check out our Saturday gallery from Spielberg, here.