Manual Valve: Notes
WARNING: This page is about a different car, the 2008 Pontiac G5 and 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
Line pressure is routed into the Low fluid circuit when the selector lever is moved into the Manual First (1) position. Line pressure continues to feed the Drive, the D321, and the D21 fluid circuits as in Manual Second.