#5 Checkball (Direct Clutch 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.
The 3-4 drive fluid pressure seats the #5 checkball, and 3-4 drive fluid is forced through the #26 orifice and into the direct clutch feed fluid circuit. the #26 orifice helps to control the direct clutch apply.