I have about 20,000 miles on my rebuilt transmission. Yesterday I started getting a strange noise from the transmission that I have no idea what it could be. When I go to drive it makes a noise that reminds me of Spongebob playing his nose like a flute and I should have a stomach ache over it but it makes me laugh. It makes a whistle noise that starts high and goes lower in pitch and when I take it out of drive it makes the same noise but goes from low to higher pitch. Either way it only makes the whistle noise for a second at most. My trans builder and I are stumped although we havent taken the pan off yet. Full of fluid and fluid smells and looks fine, hardly any towing since rebuild and definitely nothing over 9,000 lbs. Anyone ever hear this crazy noise?