#3 Checkball (Intermediate Band Apply)
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.
Intermediate band fluid pressure seats the #3 checkball and is forced through the #8 orifice. This orifice helps to control the intermediate band apply.