Circuit/System Description

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.

Transmission fluid is drawn from the bottom pan through the filter, case assembly, channel plate assembly, control valve body assembly, and into the oil pump assembly. The pump is mounted on the control valve body assembly. Fluid pressure leaving the pump is controlled by the pressure regulator valve and becomes the main supply of line pressure to the various components and hydraulic circuits. Hot fluid from the torque converter, the primary source of heat in the transmission, flows through the torque converter clutch (TCC) control valve into the oil cooler supply line. The oil cooler supply line connects to the oil cooler, which is located in the vehicle radiator and auxiliary oil cooler, if equipped. Cool fluid then returns by way of the oil cooler return line to lubricate the final drive assembly and other components along the output shaft. After lubricating the internal components, the oil returns to the oil pan. The TFT sensor, attached to the bottom of the valve body, is part of the internal transmission wire harness and not serviced separately. The normal TFT operating temperature is -40 to +151°C (-40 to +304°F).