Circuit Description

WARNING: This page does not describe the selected car, but rather 36 other vehicles, including the 2002 Pontiac Firebird, 2002 Oldsmobile Bravada, 2002 GMC Yukon XL, 2002 GMC Yukon, and 2002 GMC Sonoma. However, it is still accessible from the selected car via links, so may be relevant.

Flow of transmission fluid begins in bottom pan and is drawn through filter, control valve body, transmission case and into oil pump assembly. Oil pump assembly pressurizes fluid and directs it to pressure regulator valve, where it becomes the main supply of fluid to various components and hydraulic circuits in transmission. Hot fluid exiting torque converter flows through converter clutch apply valve and into transmission cooler lines to oil cooler and auxiliary cooler, if equipped. From cooler, fluid returns to cool and lubricate front of transmission. In forward drive ranges, "D4" fluid from manual valve is routed through an orificed cup plug in rear of transmission case to feed rear lube fluid circuit. DTC P0218 is set if PCM detects a high transmission fluid temperature for extended periods of time.