#11 Checkball (Third Clutch, Orificed Third Clutch)
WARNING: This page is about a different car, the 2009 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
The #11 checkball is located in the case cover. Third clutch pressure seats the checkball, which routes fluid through orifice #31, where the fluid enters the orificed third clutch circuit. Orificed third clutch fluid is also routed to the 2-3 accumulator valve, to the 1-2 & 3-4 accumulator valve, and to the TCC solenoid valve.