Stuck clutch on 970 john deere tractor?

Warm the tractor up at high idle for at least 15 minutes. Lower idle, and force it into gear in a safe area. Drive around at high rpm depressing the left and right brakes hard----and until the clutch breaks free. Or chain the tractor to a tree, by the draw bar only, and drive away. Avoid the problem by keeping the clutch depressed when the tractor is not in use. Jam a piece of wood between the clutch and whatever is nearby.