Lube 1
WARNING: This page is about a different car, the 2004 Pontiac Sunfire, 2004 Chevrolet Classic, and 2004 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
Cooler fluid is routed through the transmission oil cooler, which is located in the vehicle radiator, and into the lube 1 fluid circuit. Lube 1 fluid is routed through the input shaft in order to lubricate the transmission components in the front of the transmission.