[corning_d3]

This is the transmission pump whining. I've heard many lumina's and monte's that whined many miles, including mine. While in low gear, there is a boost valve that boosts pressure, increasing pump output, making it whine. This is done olny in 1st and reverse to help keep the clutches from slipping. After it shifts to second, it no longer requires as much pressure to hold the clutches. Ever heard a ford power steering pump whine(not many HAVEN'T)? The trans pump in your vehicle is the same design. I wouldn't worry about it until it turns into a growl.