3-4 Shift Valve (362)
WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
Is downshifted when D3 fluid is fed to the valve. In this position input clutch feed fluid enters the input clutch passage. 4th clutch fluid is exhausted through an orifice.