Hybrid Low, 1-2 Clutch Boost Valve
WARNING: This page is about a different car, the 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Hybrid low, 1-2 clutch boost valve spring force moves the hybrid low, 1-2 clutch boost valve to the released position, allowing HL 12 clutch/4th clutch feedback fluid pressure to exhaust into the HL 12 clutch/4th clutch feed circuit.